The Dutch motorways are under pressure due to increasing traffic intensity, ageing infrastructure, and limited physical space (Rijkswaterstaat, 2025). These issues, particularly at interchanges, lead to challenges in creating safe and future-proof designs. In this study, the development of a redesign for the Harmsenknoop interchange was used to explore how design concessions influence traffic safety and flow. Concessions are defined as modifications to the ideal design that are necessary to make it spatially feasible, such as reducing the curve radius or lowering the design speed. ... Read more

This study focuses on optimizing the efficiency of single-lane roundabouts for connected automated vehicles (CAVs). While roundabouts are vital for traffic management, their performance declines significantly under high traffic volumes. By leveraging vehicle-to-vehicle communication and the cooperative decision-making capabilities of CAVs, this research develops a microscopic control model that not only minimizes sojourn times (maximizes efficiency) but also provides precise trajectory control for each individual vehicle. Besides, a theoretical M/G/1/k queueing model is employed to calculate the expected sojourn time, serving as a baseline to compare CAV-controlled scenarios with human-driven conditions. The results demonstrate that the proposed microscopic control model significantly reduces the expected sojourn time for vehicles entering the roundabout. For a single-lane roundabout with a capacity of 17 vehicles per leg, compared to uncontrolled scenarios simulated in VISSIM, the control model achieves empirical efficiency improvements of 26%, 80%, 91%, and 90% under arrival rates of 200, 400, 600, and 800pcu/h per leg, respectively. These empirical findings align closely with theoretical predictions from the M/G/1/k queueing model, which estimate efficiency gains of 18%, 78%, 89%, and 90%. Moreover, the control model demonstrates robustness under extreme traffic conditions, maintaining high efficiency and passenger comfort. This research provides valuable insights into the integration of CAVs into traffic systems and contributes both practically and theoretically to the modernization of roundabout traffic management. ... Read more

In the Netherlands, roads are classified into three categories: access roads, distributor roads, and through roads, each with distinct functions and design criteria. Nonetheless, within built-up areas, some roads have characteristics of both access and distributor roads, leading to inadequate separation of various traffic flows while having a speed limit of 50 km/h resulting in a heightened risk of accidents. These are so-called 'grey roads'. To improve road safety on grey roads, recent adjustments have been made to the design requirements. Whereas the standard speed limit on distributor roads was previously 50 km/h, it is now 30 km/h unless 50 km/h can be safely implemented. The requirements for when a road is safe enough for a 50 km/h speed limit have been tightened. Nevertheless, a combination of parallel parking and a speed limit of 50 km/h are still permitted in these tightened design requirements. Literature indicates that roads with parallel parked vehicles have an increased risk of accidents and that higher speeds increase the impact of an accident.

Due to the recent implementation of these design requirement adjustments, there is insufficient data on road accidents to determine whether road safety would improve by lowering the speed limit to 30 km/h on roads with parallel parking. Therefore, a surrogate safety measure was necessary. In this research, situational workload was chosen as the surrogate safety measure. This thesis investigated the following research question: "What is the effect of parallel parking in combination with speed reduction from 50 km/h to 30 km/h on the driver's situational workload, the feeling of safety and credibility of the speed?".

Situational workload was derived from the concept of 'mental workload,' which refers to the dynamic relationship between a driver's capabilities and the task demand. A driver maintains control over the vehicle and adequate situational awareness if the task demand is within their capabilities. If the task demand exceeds the capability, the situational awareness is endangered and the risk of making errors increases. Changes in mental workload are often assessed using primary or secondary task performance measures: physiological measures, or subjective reflections. This research does not capture the full task demand or the complete capabilities of the drivers, since virtual reality (VR) was used as a research methodology. Consequently, it is unclear what each driver's baseline mental workload is, how it is affected by parallel parking and speed, and whether the increase in mental workload endangers driving performance.
To address this, the term situational workload was introduced in this study. Situational workload captures the influence of road conditions on self-estimated driving performance, self-reported situational awareness, and self-reported workload, based on a combination of subjective reflections and primary task performance measures. The self-estimated driving performance was assessed by evaluating the collision avoidance estimation and the situational awareness was measured by the level of overview on the road. The self-reported workload was complemented by the self-reported level of attention required for the driving task to measure the difficulty of the driving task...

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In the upcoming years more train passengers are expected and with more trains on the tracks railway systems require greater resilience. Switches can play a major role during disruptions as they enable trains to be rerouted onto other tracks, allowing them to bypass the disruption but switches also facilitate overtaking, meet-pass operations at stations as well as diverging and merging at junctions. Since switches consist of numerous parts and the fact these are moving infrastructure elements they are subject to failure itself. Maintenance is expensive and ProRail, the Dutch infrastructure manager, only has a limited budget from the government and if certain switches are only used during disruptions it sounds logical to remove those switches. With on average 50 disruptions per day in the Netherlands with both small and huge impact, it is important to get insights into the relationship between resilience and the location of the switches.

In this thesis a model is constructed that evaluates the impact of a set of disruption scenarios on different switch configurations. Four key performance indicators are found in literature that can measure resilience quantitatively: costs (number of switches), rate of cancelled services, punctuality and time to recover. In interviews with rail experts, weightings for the four KPIs are derived which are used to calculate a score for all disruption scenarios and infrastructure layouts. A trade-off between costs and resilience is made in order to find the optimal switch configuration for a double track and four track layout which provides the highest capacity during disruptions. The set of disruptions including cause, location and duration come from an extensive analysis of disruption events of the past 6.5 years in the Netherlands.

Currently, NS is cancelling many trains since NS is examined on punctuality and not on the number of trains. This research aims to cancel as few trains as possible which is also examined in a case study where the model is validated. The Dutch railway line Utrecht Centraal – Arnhem Centraal appears to have a weak spot and by proposing new switch location configurations on a part of this line the score increased, despite the fact that more switches have been included in the proposed solution. Since the big renovation, 108 switches in Utrecht Centraal were removed by ProRail which improved punctuality, capacity and speed but decreased the flexibility: a disruption between Utrecht and Arnhem (or Eindhoven) currently has a lot of impact on the train service between Amsterdam and Utrecht, because short turning options in Utrecht are rare. This means that trains are now being cancelled completely or short turn already in Amsterdam. By using smart options with new rerouting strategies, capacity between Amsterdam and Utrecht can be kept high with the proposed solution during a disruption between Utrecht and Arnhem or Eindhoven. ... Read more

In the coming decade, Advanced Driver Assistance Systems (ADAS) will play a crucial role in improving traffic safety within the European Union (EU). Notably, the European Commission mandates that from July 2024, all new vehicles must be equipped with Lane Keeping Assistance (LKA) systems. LKA systems provide force feedback to drivers when vehicles cross lane markings, employing cameras, radar, or LiDAR systems for lane detection.

To optimize LKA performance, this research focuses on understanding the influence of lane marking properties and adverse scenarios on detection ability.

Field Test and Setup:
A field test was conducted at a track in Lelystad, featuring various state-of-the-art lane markings: an old white paint lane marking as a reference, and three new lane markings (two tape types from 3M and one cold spray plast from Triflex). Lane markings were tested under dry and wet conditions.

Data Collection:
Measurements included luminance coefficient (Qd) and retroreflectivity values (Rl for dry and Rw for wet) of lane markings and asphalt, along with contrast ratios. Test runs were conducted during sunset, in complete darkness, and under different scenarios involving oncoming traffic and street lights.

Analysis and Findings:
After analyzing 414 valid runs, key findings were identified:

Lane markings are 3.3 times more likely to be detected in dry versus wet conditions.
Driving towards a light source reduces detection likelihood by 4.5 to 5 times compared to driving away from the light.
Higher wet retroreflectivity (Rw) improves LKA system performance.
Oncoming traffic with main beam headlights reduces detection likelihood significantly.
Bright light sources negatively affect contrast in camera-detected images.
New lane markings outperform old white paint markings by 2.1 to 4.3 times in detection likelihood.

Implications and Recommendations:
The study confirms the importance of lane marking detectability for LKA systems reliant on cameras. Enhancing retroreflection and contrast improves detection ratios, thereby enhancing traffic safety and potentially preventing accidents. Further research is recommended on the impact of oncoming traffic and street lights, including light type and brightness.

For future lane marking developments, testing under adverse conditions with varying light sources and wet surfaces is advised to optimize LKA system performance and ensure safety on the roads. ... Read more

Bicycles have an important role to play in the transition towards a more sustainable mobility. In order to achieve the modal shift towards bicycles, more must be done to accommodate cyclists. Although controlled intersections do increase the (perceived) safety of crossings with motorized vehicles, they are seen as major obstacles, and cyclists tend to avoid them when possible. The negative effects of controlled intersections for cyclists may be reduced by new methods of intersection control. This thesis combines the concepts of the connected environment and structure free control, to design an intersection controller that uses a genetic algorithmto determine the optimal signal plan, hereafter referred to as the SFGA controller. The controller is designed for an isolated intersection and considers car drivers and cyclists. Desires of cyclist with regard to controlled intersections, are identified by means of a literature review on the determinants of bicycle use, which are then projected on the controlled intersection. A traffic system model, based on validated models found in literature, is set up and a design for the structure free controller is proposed. A set of control objectives is proposed, including different metrics related to the desires of cyclists and car drivers. Objective function weights can be varied to achieve different levels of cyclist prioritization. A maximumwaiting time of 100 seconds is enforced in order to prevent prioritization of cyclists to result in unreasonable delays for car drivers, because red light running probabilities increase at larger waiting times. The performance of the structure free controller is evaluated for 15, 35 and 45% traffic saturation (percentage of intersection capacity), by means of a simulation based case study. The designed controller is benchmarked to vehicle actuated control (VA). VA has a cyclic, fixed control structure in which green times of movements are flexible and depend on the queue size. SFGA is benchmarkedwith an equalweight for the delay of car drivers and cyclists, and no weight included for the number of stops. The effect of incorporating weights that prioritize the desires of cyclists over those of car drivers is investigated. The SFGA controller results in average delays 1.8, 2.7 and 3.0 times lower than VAC for each of the evaluated traffic saturation levels. The number of stops is 1.9, 2.3 and 3.1 times lower. Including weights in the objective function to explicitly prioritize cyclists, results in even lower average delays and number of stops for cyclists. As is to be expected, this comes at the cost of additional delays for car drivers, especially for higher traffic saturation. The better performance of SFGA is attributed to two main differences between the controllers. First of all, the structure free aspect allows for a larger degree of freedom to choose more effective combinations of traffic lights to show green at the same time, instead of following the fixed sequence of VA. Additionally, the controller allows traffic that otherwise would experience the largest total delay to cross first, even if this means delaying some travellers in close proximity of the traffic light. This contrary to VA, that extends green time based on detected traffic in the active block. Without inclusion of weights that prioritize the desires of cyclist over cars, the controller already tends towards prioritization of the cyclists. This is caused by the controller considering the number of travellers that are influenced by its’ control decisions, combined with the higher traffic densities, that can be expected on bicycle paths in urban areas. Weights to prioritize cyclists can be included to include more priority, for example when bicycle traffic volumes are low. This work implicates that, in order to better serve the cyclists, it is not explicitly required to prioritize cyclists over cars. In areas with large volumes of cyclists, considering the number of travellers and their proximity to the traffic light can already result in cyclists being served better. This work could be used as a starting point or inspiration to design and eventually implement more cyclist oriented intersection controllers. Improvements for the controller and extensions for the research scope are proposed that are required for the controller to be suitable for practical implementation in the real world. If a future version of the controller is to be implemented, it will reduce the negative effects of controlled intersections on cyclists, thereby making the bicycle a more suitable replacement for the car. ... Read more

Deze scriptie beschrijft een onderzoek naar de toepasbaarheid van verschillende pop-up fietspaden. Dit zijn fietspaden welke in zeer korte tijd kunnen worden aangelegd en in een latere fase definitief worden gerealiseerd of weer verdwijnen uit het straatbeeld. Aangezien pop-up fietspaden in de meeste gevallen op dezelfde rij loper liggen als auto’s voorheen gebruikte is een rijbaanscheiding van belang.
Eerst is onderzocht welke type pop-up fietspaden bestaan en hoe deze onderverdeeld kunnen worden. Voor dit onderzoek is gebruik gemaakt van een enquête welke is verspreid in Duitsland, Frankrijk en Nederland om de gebruikerservaringen van pop-up fietspaden te bepalen.
Uit dit onderzoek blijkt dat Barrières afgezien van kosten erg goed scoren. Een parkeerstrook als rijbaan scheiding is een goede optie mits voldoende ruimte aanwezig is en de weg geen stroomweg is.
Lijn markering zijn qua kosten voordelig maar moeten desondanks zo min mogelijk gebruikt worden. Net als bij normale fietspaden is de ligging van invloed op de veiligheid van fietsers. In verschillende landen hebben fietsers verschillende voorkeuren voor de ligging van een fietspad. Ook de regelgeving
is verschillend hierover tussen verschillende regio’s. Uit dit onderzoek blijkt dat rijbaanscheidingen inwisselbaar zijn per type wegindeling. Om een keuze voor een optimale rijbaanscheiding te maken kan gebruik gemaakt worden van een keuze diagram op basis van snelheid van auto’s en beschikbare
ruimte. Voor de wegindeling hebben alle types specifieke karakteristieken. Afhankelijk van de intensiteit lokaal of doorgaand fietsverkeer kan gekozen worden welk type wegindeling het beste bij de weg past aan de hand van een keuze diagram. ... Read more

Traffic signals in a coordinated network normally use a common cycle length which remains constant at all times, including when there is a request for priority from a public transport vehicle. This enables green waves to be maintained effectively but can limit the signals' ability to promptly serve the prioritised vehicle.

To study the effects of momentarily relaxing the constraint of cycle length during Transit Signal Priority (TSP) interventions, a new TSP system is developed for a CRSV halfstarre traffic signal controller, which permits a flexible cycle length during priority interventions. That system is tested using a Vissim microsimulation of a simple fictional network, and compared to the existing fixed-cycle-length TSP system included with the controller.

The new TSP system permits TSP actions as long as it is expected that the signal can return to its normal "in sync" timings within two cycles. During the intervention, the positive and negative impacts on each signal phase are monitored, and "Offset Correction Credits" are distributed, which each represent one second of additional green time. Signal phases which received extra time during the TSP intervention will receive negative OC Credits, and phases which were truncated will receive positive OC Credits. Once the intervention is complete, the signal will execute "offset correction" to return the signal to its normal "In Sync" timings while redeeming OC Credits.

The subject road network consists of fictional road with three coordinated traffic
signals, spaced 150 metres and 400 metres apart. The central intersection is the capacity-critical intersection and also includes a frequent bus line (12 buses per hour per direction) travelling along a median busway perpendicular to the coordinated direction.

In the scenario with a high flexibility to reduce green durations, the average delay for late buses dropped by 59% from 10.7 secondsto 4.4 seconds for the flexible-cycle system compared to the fixed-cycle system. With low flexibility, the average delay for late buses dropped by 78% from 28.0 seconds to 6.2 seconds. The large improvements in performance for buses are due to the flexible-cycle TSP systems being able to execute more TSP actions such as phase insertions which may not fit within a fixed cycle length.

However, the controller’s ability to remain in sync was negatively impacted and the frequency of queues exceeding storage increased by as much as 70% on short roadway links. However on long roadway links, delaysand queue lengths decreased in the coordinated directions thanks to the new TSP system’s green time compensation mechanism.

When the assumed occupancy rate for late buses is 50 passengers (corresponding to a busy but not overcrowded standard bus), there was no significant difference in person-delay between any of the scenarios. Early buses were not included in the calculation for average person-delay. ... Read more

Intersections are the bottleneck of traffic flow. Vehicle-actuated control improved the delay at an intersection by making the green phase variable based on the presence of vehicles as measured by detector loops. The duration of the yellow and red phase remains fixed times because intentions of specific human-driven vehicles (HDVs) are unknown, and measurements of the behaviour of HDVs at crucial moments can not be provided by detector loops. The introduction of connected autonomous vehicles (AVs) will bring a transition (hybrid) period, where HDVs and AVs share the road. Intersection controllers for this period have been proposed, but none of them improve delay at low penetration rates. The AVs could be used to provide additional information at crucial moments. This research proposes a new controller for the complete range of penetration rates of AVs, in which the controller aims to shorten the yellow and red phase. The information of the AVs is used to identify the scenario at the intersection and apply control actions based on predictions. Simulations revealed that the yellow and red phase are shortened from low penetration rates (2%) onwards but that the delay compared to the original controller only decreases after at penetration rates of 10% and higher. ... Read more

In this thesis, the significance of the so-called ‘induced demand’ phenomenon is discussed. This phenomenon can occur when a stretch of road which is prone to congestion is widened. Although this widening should in theory solve congestion problems, it can often spawn additional effects, typically undesired and occasionally unforeseen. These effects could include shifts of travel in route and time (people formerly avoiding congested roads by departing at another time or taking a detour will now return to that road), but also new travels might be made which were not made before road widenings. All of these effects might eventually converge to raise traffic amounts to levels with which the widened road is just as prone to congestion as it was. This additional traffic demand which a widened or new road creates is commonly denoted as ‘induced demand’.
Although this induced demand phenomenon has commonly been acknowledged to exist, it seemed like there was little agreement on both its amount as well as its significance. Some readings seemed to suggest that for every percent of road capacity added, a percent of new traffic will occur, whereas other readings suggested that the effects were much smaller and might be limited to, e.g., merely a third of a percent extra traffic for a percent extra road capacity. A semi-systematic literature review has been carried out, enabling to compare writings of various origins, ranging from scientific papers via documents from governmental advisory bodies to newspaper articles for the general public.
These writings help to determine the significance of induced demand. It has been found that there are major discrepancies, even amongst scientific literature, concerning the ways in which the induced demand is measured, both in terms of the actual quantities which are compared to each other, as well as the time span over which the aforementioned effects are measured. These discrepancies do not aid in creating an unambiguous message for policymakers, nor do they facilitate a straightforward approach in avoiding new congestion on widened roads. Combined with the remark to be found in many scientific writings that the induced demand topic is in need of more research, a relayed recommendation from this thesis is therefore that more research be performed into this topic. However, the main recommendation is that the newly done research be more standardised, both in terms of the measured quantities and the time span over which the effects are measured. ... Read more

The Netherlands is like no other country enthusiastic about cycling and is the home of 37.000 kilometers of bicycle paths. These bicycle paths need to cross other modalities and therefore intersections are needed. At signalized intersections, the control is mostly regulated using sensors such as push buttons and one or multiple inductive loops. Sensors for cyclists are running slightly behind in comparison with those from cars and the company of CycleData anticipated on this fact by developing a new sensor, the iSignum, that works on radar and laser service and is capable to determine speed. The iSignum is capable of communicating with the iVRI (intelligent traffic light control) where it is installed and notify that a cyclist is coming. The sensor is placed further away from the stop line meaning there is time to communicate with the iVRI that a cyclist was detected and for example with what speed. This can benefit the comfort and traffic flow of cyclists when a notification leads to green light such that cyclists simply do not have to stop unnecessarily before the intersection. Part of this research was a literature study towards stakeholders and existing bicycle sensors. The latter was needed to be able to make a comparison of what makes the iSignum stand out from the rest or if it is just another bicycle sensor. A literature study has indicated that inductive loop sensors in combination with push buttons are used the most. Additionally, there are other cyclists sensors on the market nowadays. These sensors include infrared sensors, smart cameras and mobile phones and WiFi/Bluetooth applications. These are however not used on a big scale yet. In this report, research was done towards the newly developed sensor that is installed at an intersection in Delft, the Julianalaan-Nassaulaan intersection. Several matters were looked into, such as the accuracy of the iSignum in comparison to the reality at this location and what potential situations can result in disturbances in detecting cyclists. Furthermore, preventions are explored to an extent of what could be possible at this specific location. To test the exactness of the iSignum, manual bike counting is done over the course of three days. This data was then compared to the data that the sensor of iSignum logs. Conclusions that have been made after the comparison is that the newly developed sensor is not as accurate as the company CycleData claims it to be, the promised 95% is not reached. During the measurements, the sensor did not manage to pass the 78.2% accuracy. However, disturbances that happened, such as the presence of a delivery van or garbage truck or cars that drive over the bicycle path, while counting cyclists are included. Making the preciseness less in particular cases, with the worst case being 75.3%. V-log data, which logs traffic status and information such as detection and signal groups from an iVRI, is additionally used to check whether those disturbances can be covered by the existing control of the intersection. The outcome states that the existing intersection control of a loop sensor and push-button manage to still detect cyclists during the time of disturbances. Next to this, prevention methods for the disturbances are researched such that relying on the existing intersection control may not be needed in the future and the full potential of the iSignum can be reached after more precision from the sensor itself is achieved. A prevention method that could help all the occurred disturbances is to move the sensor more downstream from the bicycle path where the disturbances do not influence the sensor anymore. This is therefore also the recommendation for this particular intersection such that unnecessarily errors are filtered out of the data. Additionally, further research is needed after the relocation of the sensor and towards the enhancement of the accuracy because other errors are present that are not accountable to a disturbance. It is valuable to do more extensive research on this topic to determine if these errors can be erased from the system to reach the full potential of the iSignum such that the objective of shorter waiting times and more comfort for cyclists can be reached at signalized intersections. ... Read more

Many municipalities try to encourage cycling in their cities to increase the use of sustainable modes of transport and decrease congestion. They therefore implement innovative traffic solutions such as `green wave'-apps for cyclists. These `green wave'-apps influence the green phase of traffic lights by requesting a green light earlier than conventional detectors would. These apps have already been implemented in several municipalities in the Netherlands and Germany, but not much research has been done into this kind of apps. The goal of this thesis was to determine how these apps can contribute to the cycling experience and benefit both cyclists and municipalities.

This thesis involved a literature review, theoretical case studies into the potential effects of the apps, interviews with municipal employees and app developers, and a small survey among app users.

This research showed that when the request of a green light can be granted immediately, the use of a `green wave'-app can decrease the travel time of an average cyclist with up to 4.4 seconds per intersection. When an intersection already has more than one detection loop for cyclists, the advantages of using a `green wave'-app are more noticeable for the faster cyclists. Interviews with municipalities showed that the few reactions they got from users of the apps were mainly positive, but for most cities, specific results of the apps are not yet known due to a low number of users and a lack of research. Only in Enschede and in Marburg (Germany), a decrease in average waiting times for cyclists seemed to be found in research.

The respondents to the survey showed mixed experiences, which was in line with the results of a survey conducted in Enschede. Some respondents did not experience benefits from using the app and stopped using it. More frequent users more often seemed to experience an increase in the number of times they got an early green light while using the app. Suggestions from respondents for possible improvements of the apps mainly focused on the implementation at more intersections. Municipalities saw possible improvements in the feedback to the users in the app. More information about where and when a cyclist got an early green light while using the `green wave'-app could increase the transparency of the app and show users the benefits from using it.

The results indicate that the existing `green wave'-apps for cyclists can contribute positively to the experience of cycling and already seem to decrease waiting times for cyclists in some cities. This more positive cycling experience could theoretically contribute to the popularity of cycling and help municipalities encouraging bike usage. However, experiences of cyclists are not all positive. The suggested improvements of the apps could help to improve user experiences and further increase the number of users. Further research could simulate the impact of the use of these apps on traffic flows at intersections or look at the importance of the route prediction compared to only GPS-tracking.
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In 2019 a virus surfaced in China that would later cause a pandemic: the coronavirus. Across the world measures were taken to reduce the spread of the virus. Public Transport (PT) had a unique position, being both an essential service and a place where the virus can easily be spread. This research investigates the measures taken in PT in the Netherlands and internationally in an objective manner. No assessment is made of any kind of any measure. In the Netherlands, the Outbreak Management Team collaborated with the public transport association OV-NL to ensure every companies response was similar. Through an interview with the chairman of OV-NL, Pedro Peters, more information was gathered on this particular aspect of the research. Besides taking measures to reduce the virus, mainly by reducing or avoiding contact (both between people and with surfaces), companies reduced their service levels. This reduction was a response to the large decrease in passenger demand and partly to more of the personnel reporting sick. This research investigated this reduction of service throughout the first period of the virus outbreak in the Netherlands (27th of February – 1st of June). Besides the Netherlands, measures taken in other countries were also investigated, showing many similarities. However, other measures were taken as well, like checking the temperature of passengers in for example Thailand, China or Iran or using a proximity app which happened in Singapore. Not every country experienced the virus outbreak at the same time. In the research, data by the Oxford University and Blavatnik School of government was used to create world maps that visualize the closing of public transport for all days of the outbreak up to June 1st. The same was done to create a map for lockdowns and using data found through an online search a world map visualisation was made about the mandatory use of face masks in public transport. The maps show a general trend: following the virus, but it is clear that some countries responded early or late and that the correct response to the virus was unclear. Especially the face mask visualisation shows a more random pattern. So while within the Netherlands the response to the virus was uniform, internationally the response was quite random. This research can be used to further research the measures taken and assess the measures with regards to for example effectiveness, safety or comfort. ... Read more

With the arrival of Connected and Automated Vehicles (CAVs) concepts for traffic control systems emerge that let CAVs weave over the crossing area of an intersection. However, in the current literature, the safety of these vehicles is generally an assumption rather than a certainty. Moreover, the time period where CAVs and Human-Driven Vehicles (HDVs) share the road (i.e. hybrid traffic period) is often not considered by the design of these concepts.
This paper describes technical and non-technical factors that influence the actual and perceived safety of passengers of HDVs and CAVs during the vehicle interactions that occur in the hybrid traffic period. The impact of the indicated factors on the actual or perceived safety of a vehicle is analyzed and described in terms of required safety margins around a vehicle. The size of the safety margins described depend on the positioning inaccuracy of the vehicle, its trajectory tracking inaccuracy, a time synchronisation inaccuracy, and on the preferred time headway, preferred driver space, and accepted time gap of the car occupants. Due to a lack of available data that could be used to compare the expected size of the safety margins around the vehicle with, this research presents a methodology to generate own data that could be used for this comparison. A virtual reality experiment was executed among 82 participants, which resulted in a 93\% acceptance rate at a time gap of 1.5 seconds between one vehicle leaving and another vehicle entering their conflict area. It appeared that neither the crossing direction (left, right) nor the vehicle composition (HDV, CAV) of a vehicle interaction scenario influenced the perceived safety margins in front of the vehicle. The experiment found lower perceived safety margins in front of the vehicle than was expected according to the literature study. This may be the result of the sample not completely being comparable to the total drivers population. 2.0 seconds was accepted by 99\% of the participants. The question arises what acceptance rate is desired to determine the minimum time gap that can be used as a perceived safety margin by future traffic control systems. The accepted time gap is expected to decrease as soon as more drivers get experienced with CAVs. ... Read more

To evaluate traffic signal controllers, and vehicle-actuated traffic signal controllers in particular, in terms of how they are performing with respect to the road authority’s policies on traffic flow and accessibility, traffic safety, and environmental factors, several methods are developed in practice. However, in scientific literature, little attention is paid to this type of traffic signal controller evaluations. Indeed, it is found that a functional, and integral evaluation and diagnosis method for traffic signal controllers, based on a multi-variable assessment, is currently lacking. This thesis tries to fill this gap, by developing, and presenting an integral method, which detects inefficiencies in terms of traffic performance functioning, scores the vehicle-actuated traffic signal controller, diagnoses the cause of the detected inefficiency, and propose countermeasures to improve the traffic performance functioning of the vehicle-actuated traffic signal controller, based on a multi-variable assessment. This resulted in a five-step procedure, in which consecutively (1) the multi-variable performance indicators are selected, (2) the computational models are calibrated, (3) inefficiencies are detected, (4) the problems are diagnosed that caused the inefficient performance, and (5) optimises the traffic signal controller by implementing the countermeasures that aim at mitigating the diagnosed problems. The procedure includes a feedback loop to check whether the proposed countermeasures were effective. The testing of the method in a case study, using simulation data, showed that the method is indeed able to successfully detect inefficiencies, and diagnose the corresponding problems. Although the presented method is not perfect yet, its potential is clear. Therefore, it is recommended to develop the method further in the future, and include the use of data from practice as a way to make the method more widely applicable. ... Read more

This research investigates the influence of priority road markings on cyclists’ behaviour at bicycle street crossings. Almost all bicycle street crossings are controlled by priority markings or by the priority rule: traffic coming from the right has priority. At these crossings there is a lot of interaction between cyclists, so it is important that the bicycle traffic can pass the crossings without severe conflicts. For the research two crossings were observed. One crossing with priority markings and one without priority markings, both with traffic from four directions.
At both crossings a camera recorded the cyclists passing the crossing for one hour at three different moments in the day. The conflicts on the footage are investigated in the analysis. Firstly, It was investigated if priority was given when it should have been given. Also the severity of the conflicts and the behaviour of the cyclists who had to give priority were classified. Finally the influence of the kind of crossing (crossing or merging), the influence of groups and the influence of scooters were addressed.
The results show no relation between the presence of a scooter in a conflict and the percentage of cyclists not giving priority while they should have given priority. Also merging and crossing conflicts show no large difference in priority behaviour. But when groups are part of a conflict, priority is less often given while it should have been given. After these three influences, conflicts in general are compared for a crossing with priority markings and a crossing without priority markings. The observed crossing without priority markings shows a larger percentage of severe conflicts. Also the cyclists who had to give priority show more often reckless behaviour in conflicts. From these results it is concluded that priority markings control the priority on a crossing better than the priority rule: traffic coming from the right has priority. ... Read more