M. Snelder
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12 records found
1
Building-level pedestrian trip generation
For Dutch urban areas using open data
To address this gap, this study develops a building-level pedestrian trip-generation model with fine spatial and temporal resolution, tailored to Dutch conditions and relying exclusively on widely available open data. The central research question is: To what extent can an existing pedestrian trip-generation model be adapted to reflect pedestrian trip-generation dynamics in the Dutch urban context?
The study adapts Sevtsuk’s Urban Network Analysis (UNA) framework into a Dutch-specific, building-level model referred to as BPT-Gen (Building-level Pedestrian Trip Generation). The UNA framework was selected because it offers a practical balance between spatial detail and data requirements while remaining transparent and reproducible. Several key adaptations are introduced to ensure applicability to Dutch cities.
First, buildings are identified and classified using the Dutch BAG dataset, supplemented with OpenStreetMap (OSM) data to capture land use, amenities, and public transport facilities. This enables a detailed and consistent representation of pedestrian trip origins and destinations at the building level.
Second, the derivation of building activity weights is modified. These weights represent the estimated number of unique daily users per building. Where detailed local data are available, weights are calculated directly; otherwise, Dutch building and occupancy standards or carefully selected proxy indicators are applied. This approach allows the model to remain operational across data-limited contexts while explicitly acknowledging uncertainty.
Building on the UNA framework, the model incorporates accessibility-adjusted activity weights. Each building is connected to the pedestrian network, and destination-specific Reach indices are calculated using a walking radius relevant to Dutch conditions. These indices adjust baseline activity weights to account for behavioural tendencies and destination attractiveness. Sensitivity analyses examine how assumptions regarding walking radius and normalisation methods influence model outcomes.
A major extension beyond the original UNA framework is the integration of temporal dynamics through hourly walking trip rates. Trip purposes derived from the Dutch ODiN travel survey are mapped to building types, and corresponding hourly origin–destination trip rates are applied. Combining these rates with accessibility-adjusted weights yields hourly, building-level pedestrian trip-generation estimates for the study area.
Model performance is assessed through face validation using observed pedestrian counts. Results show that the adapted model reproduces realistic spatial and temporal patterns for building types supported by reliable activity data, particularly housing and major train stations. Underprediction is observed for offices and leisure facilities, where activity weights rely on proxy indicators and where walking trips are likely underreported in ODiN. Sensitivity analyses confirm that trip-generation outcomes depend strongly on proxy selection and accessibility assumptions, revealing structural uncertainties.
Despite these limitations, the BPT-Gen model provides clear practical value. It identifies key generators of walking trips, peak periods, and accessibility-driven hotspots using only open data. By linking trip purposes to building types at hourly resolution, the framework fills an important gap in Dutch pedestrian modelling and offers a transparent foundation for future extensions. The findings demonstrate that open-data pedestrian models can provide meaningful planning insights while highlighting the need for improved activity indicators and further validation using street-level pedestrian flow data.
...
To address this gap, this study develops a building-level pedestrian trip-generation model with fine spatial and temporal resolution, tailored to Dutch conditions and relying exclusively on widely available open data. The central research question is: To what extent can an existing pedestrian trip-generation model be adapted to reflect pedestrian trip-generation dynamics in the Dutch urban context?
The study adapts Sevtsuk’s Urban Network Analysis (UNA) framework into a Dutch-specific, building-level model referred to as BPT-Gen (Building-level Pedestrian Trip Generation). The UNA framework was selected because it offers a practical balance between spatial detail and data requirements while remaining transparent and reproducible. Several key adaptations are introduced to ensure applicability to Dutch cities.
First, buildings are identified and classified using the Dutch BAG dataset, supplemented with OpenStreetMap (OSM) data to capture land use, amenities, and public transport facilities. This enables a detailed and consistent representation of pedestrian trip origins and destinations at the building level.
Second, the derivation of building activity weights is modified. These weights represent the estimated number of unique daily users per building. Where detailed local data are available, weights are calculated directly; otherwise, Dutch building and occupancy standards or carefully selected proxy indicators are applied. This approach allows the model to remain operational across data-limited contexts while explicitly acknowledging uncertainty.
Building on the UNA framework, the model incorporates accessibility-adjusted activity weights. Each building is connected to the pedestrian network, and destination-specific Reach indices are calculated using a walking radius relevant to Dutch conditions. These indices adjust baseline activity weights to account for behavioural tendencies and destination attractiveness. Sensitivity analyses examine how assumptions regarding walking radius and normalisation methods influence model outcomes.
A major extension beyond the original UNA framework is the integration of temporal dynamics through hourly walking trip rates. Trip purposes derived from the Dutch ODiN travel survey are mapped to building types, and corresponding hourly origin–destination trip rates are applied. Combining these rates with accessibility-adjusted weights yields hourly, building-level pedestrian trip-generation estimates for the study area.
Model performance is assessed through face validation using observed pedestrian counts. Results show that the adapted model reproduces realistic spatial and temporal patterns for building types supported by reliable activity data, particularly housing and major train stations. Underprediction is observed for offices and leisure facilities, where activity weights rely on proxy indicators and where walking trips are likely underreported in ODiN. Sensitivity analyses confirm that trip-generation outcomes depend strongly on proxy selection and accessibility assumptions, revealing structural uncertainties.
Despite these limitations, the BPT-Gen model provides clear practical value. It identifies key generators of walking trips, peak periods, and accessibility-driven hotspots using only open data. By linking trip purposes to building types at hourly resolution, the framework fills an important gap in Dutch pedestrian modelling and offers a transparent foundation for future extensions. The findings demonstrate that open-data pedestrian models can provide meaningful planning insights while highlighting the need for improved activity indicators and further validation using street-level pedestrian flow data.
Forecasting Parking Occupancy
Developing a Parking Model Framework Using a Case Study on The Hague
City Clustering based on topology, activity distribution, and mobility
A study on 32 European cities using K-Means, K-Medoids, and Ward's Method
Previous studies have classified cities based on individual features like road layout or mobility patterns. While informative, these studies often overlook interdependencies between domains. This research addresses that limitation by integrating road network structure, activity distribution, and mobility behavior into a single analysis using clustering methods.
The main question guiding this research is:
How can the application of multiple clustering methods reveal distinct groups of European cities based on road network, activity distribution and mobility characteristics?
Data was obtained for 32 European cities, capturing indicators from five domains: road topology, population, economic activity, mobility, and congestion. Indicators were standardized, and redundancy was reduced through correlation analysis and Principal Component Analysis (PCA). Clustering was then performed using K-Means, K-Medoids, and Ward’s Method, and evaluated using silhouette scores, Adjusted Rand Index (ARI), and Jaccard Similarity.
The results showed that cities could be grouped meaningfully and consistently using combined structural and behavioral indicators. Two- and seven-cluster results emerged as the most stable. The two-cluster split revealed a broad regional divide, while the seven-cluster result uncovered distinct urban typologies with full agreement across methods.
This study contributes to urban transport research by offering a replicable and holistic clustering approach that uses open data and multiple analytical techniques. It shows that meaningful typologies can be created by combining structural, functional, and behavioral dimensions, helping cities identify similar urban contexts and learn from specific strategies.
Overall, this research demonstrates that multi-domain clustering offers a valuable tool for comparing cities and supporting more targeted, evidence-based planning for sustainable urban transport. ...
Previous studies have classified cities based on individual features like road layout or mobility patterns. While informative, these studies often overlook interdependencies between domains. This research addresses that limitation by integrating road network structure, activity distribution, and mobility behavior into a single analysis using clustering methods.
The main question guiding this research is:
How can the application of multiple clustering methods reveal distinct groups of European cities based on road network, activity distribution and mobility characteristics?
Data was obtained for 32 European cities, capturing indicators from five domains: road topology, population, economic activity, mobility, and congestion. Indicators were standardized, and redundancy was reduced through correlation analysis and Principal Component Analysis (PCA). Clustering was then performed using K-Means, K-Medoids, and Ward’s Method, and evaluated using silhouette scores, Adjusted Rand Index (ARI), and Jaccard Similarity.
The results showed that cities could be grouped meaningfully and consistently using combined structural and behavioral indicators. Two- and seven-cluster results emerged as the most stable. The two-cluster split revealed a broad regional divide, while the seven-cluster result uncovered distinct urban typologies with full agreement across methods.
This study contributes to urban transport research by offering a replicable and holistic clustering approach that uses open data and multiple analytical techniques. It shows that meaningful typologies can be created by combining structural, functional, and behavioral dimensions, helping cities identify similar urban contexts and learn from specific strategies.
Overall, this research demonstrates that multi-domain clustering offers a valuable tool for comparing cities and supporting more targeted, evidence-based planning for sustainable urban transport.
Bicycle Travel Demand Estimation Method
TU Delft Campus Case Study
The primary aim of this research is to identify a modeling process and specifications that are compatible with the available data, while laying the groundwork for future improvements to the bicycle network, especially TU Delft Campus. This will help ensure the system remains adaptable and relevant for long-term planning.
To identify an appropriate modeling approach, an exploratory analysis of the data was conducted. A clear pattern emerged in bicycle traffic, characterized by short-interval fluctuations corresponding closely with lecture schedules. An additional notable observation is the occurrence of an average peak in bicycle traffic during midday. These findings support a dynamic analysis approach with a 5-minute interval.
Moreover, the model incorporates specialized variables defined by the study’s scope, focusing on trip generation and trip distribution within the established four-step modeling framework, specifically tailored for Origin-Destination (OD) matrix estimation in transportation engineering.
For trip generation, linear regression coupled with backward stepwise elimination via the Ordinary Least Squares (OLS) method was employed to identify significant predictors. For trip distribution, the Iterative Proportional Fitting (IPF) method was utilized. This approach was chosen based on the assumption that impedance is minimal for short-distance travel, a scenario particularly relevant within the TU Delft campus context.
Ultimately, this methodology provides a flexible and responsive framework tailored to the specific transportation dynamics at TU Delft, producing valuable insights for optimizing bicycle network planning.
The developed model is relatively simple but exhibits several shortcomings. One significant limitation is related to data collection, as the available data lack the temporal resolution necessary to fully capture the dynamic travel patterns targeted by the model. Additionally, the linear regression approach used for modeling trip production and attraction yielded unsatisfactory results, with $R^2$ values below 0.5. Another issue is potential underfitting, as indicated by the improved explanatory power of the model when trained on smaller datasets. Validation using RMSE and comparative plots of modeled versus actual flows further confirms that substantial improvement is needed in the model’s reliability and predictive capability.
The trip distribution process, conducted using the Iterative Proportional Fitting (IPF) method, reveals additional areas for improvement. The OD matrix underestimated total production by two bicycles in a 5-minute interval. Although seemingly small, this discrepancy underscores the necessity for more robust input data and methodological refinements. Additionally, direct validation of the OD matrix is crucial to enhance accuracy and reliability in representing actual travel flows.
Despite the shortcomings, the framework provides a balance between interpretability and flexibility, enabling both accurate representation of observed travel behavior and ease of scenario testing—making it a practical tool for supporting data-driven mobility planning and policy evaluation on campus.
...
The primary aim of this research is to identify a modeling process and specifications that are compatible with the available data, while laying the groundwork for future improvements to the bicycle network, especially TU Delft Campus. This will help ensure the system remains adaptable and relevant for long-term planning.
To identify an appropriate modeling approach, an exploratory analysis of the data was conducted. A clear pattern emerged in bicycle traffic, characterized by short-interval fluctuations corresponding closely with lecture schedules. An additional notable observation is the occurrence of an average peak in bicycle traffic during midday. These findings support a dynamic analysis approach with a 5-minute interval.
Moreover, the model incorporates specialized variables defined by the study’s scope, focusing on trip generation and trip distribution within the established four-step modeling framework, specifically tailored for Origin-Destination (OD) matrix estimation in transportation engineering.
For trip generation, linear regression coupled with backward stepwise elimination via the Ordinary Least Squares (OLS) method was employed to identify significant predictors. For trip distribution, the Iterative Proportional Fitting (IPF) method was utilized. This approach was chosen based on the assumption that impedance is minimal for short-distance travel, a scenario particularly relevant within the TU Delft campus context.
Ultimately, this methodology provides a flexible and responsive framework tailored to the specific transportation dynamics at TU Delft, producing valuable insights for optimizing bicycle network planning.
The developed model is relatively simple but exhibits several shortcomings. One significant limitation is related to data collection, as the available data lack the temporal resolution necessary to fully capture the dynamic travel patterns targeted by the model. Additionally, the linear regression approach used for modeling trip production and attraction yielded unsatisfactory results, with $R^2$ values below 0.5. Another issue is potential underfitting, as indicated by the improved explanatory power of the model when trained on smaller datasets. Validation using RMSE and comparative plots of modeled versus actual flows further confirms that substantial improvement is needed in the model’s reliability and predictive capability.
The trip distribution process, conducted using the Iterative Proportional Fitting (IPF) method, reveals additional areas for improvement. The OD matrix underestimated total production by two bicycles in a 5-minute interval. Although seemingly small, this discrepancy underscores the necessity for more robust input data and methodological refinements. Additionally, direct validation of the OD matrix is crucial to enhance accuracy and reliability in representing actual travel flows.
Despite the shortcomings, the framework provides a balance between interpretability and flexibility, enabling both accurate representation of observed travel behavior and ease of scenario testing—making it a practical tool for supporting data-driven mobility planning and policy evaluation on campus.
Modelling changing travel behaviour in response to road capacity reductions
The impact of reallocating road space in urban areas on car use
Using a three-step iterative framework, the model adjusts the traffic demand based on observed travel times in response to capacity reductions. The process accounts for modal shifts, destination changes and trip frequency reduction. The methodology is applied to a real-world case study where significant road space reallocation is implemented, allowing for an evaluation of the extent and mechanisms of disappearing traffic.
Findings indicate that a considerable share of the traffic does not reroute but instead disappears due to behavioural changes. The extent of disappearing traffic depends on the severity of capacity reductions, the existing congestion levels on both intervening and alternative routes, and the availability of viable transport alternatives. The findings highlight the importance of incorporating adaptive travel behaviour in transport models to better support decision-making in sustainable urban mobility planning.
This research contributes to the growing body of knowledge on the effects of road capacity reductions and provides a modelling framework for policymakers and urban planners to anticipate and manage disappearing traffic effects effectively.
...
Using a three-step iterative framework, the model adjusts the traffic demand based on observed travel times in response to capacity reductions. The process accounts for modal shifts, destination changes and trip frequency reduction. The methodology is applied to a real-world case study where significant road space reallocation is implemented, allowing for an evaluation of the extent and mechanisms of disappearing traffic.
Findings indicate that a considerable share of the traffic does not reroute but instead disappears due to behavioural changes. The extent of disappearing traffic depends on the severity of capacity reductions, the existing congestion levels on both intervening and alternative routes, and the availability of viable transport alternatives. The findings highlight the importance of incorporating adaptive travel behaviour in transport models to better support decision-making in sustainable urban mobility planning.
This research contributes to the growing body of knowledge on the effects of road capacity reductions and provides a modelling framework for policymakers and urban planners to anticipate and manage disappearing traffic effects effectively.
Optimal re-routing strategy for CAV and HDV mixed traffic under a road closure
A simulation-based method
A rerouting strategy is designed based on the rerouting behaviour of vehicles when road closure occurs in life, the control parameters include the control of the CAV's automatic rerouting period, rerouting probability, HDV Knowledge of the time of lane closure, as well as their rerouting probability. The aim of this study is to find the optimal combination of these five parameters. Four levels of CAV penetration (20\%, 40\%, 60\%, and 80\%) are considered with the objective of minimizing the total travel time on a mixed CAV and human-driven vehicle (HDV) traffic flow network. The main question is \textbf{What is the optimal rerouting strategy for CAV and HDV mixed traffic when road closure happens?} and in the process of answering this question, the effects of CAV penetration, individual rerouting parameters and different road closure locations are considered and analyzed.
In this thesis, a simulation-based approach is used to model the traffic flow applying both micro and meso scale models. Then, the simulation is conducted for the predefined scenarios, then the sensitivity analysis of each relevant parameter is performed using a one-factor-at-a-time approach to understand the impact of each parameter on the network traffic condition. Finally, Bayesian optimisation is used to find the optimal rerouting strategy within a certain search range and number of times, where the results obtained from the sensitivity analysis are used to determine the parameter search space.
The grid network and the Sioux Falls network are simulated respectively and the relatively optimal rerouting strategies are found for them. The grid network can be regarded as a local area on the network, while the results of Sioux Falls, as a larger network, can provide some basis for city-level traffic management.
The key findings of this thesis include (1) CAV penetration increases bring reductions in TTT and TWT and increase in TTD to the network, overall, the traffic flow movement improves and severe congestion decreases, and network conditions improve significantly during the growth phases of 20\%-40\% and 60\%-80\%; (2) the importance of each rerouting parameter varies for different networks and at different penetration rates, and the results fluctuate significantly between different test values, with no single increasing and decreasing trend; (3) road closures at entrances and exits located at intersections are more critical and require targeted rerouting strategies; the traffic demand distribution has a significant impact on it; (4) Bayesian optimization can find the optimal rerouting strategy in a finite amount of time, where the specific strategy and the improvement effect varies for different networks and levels of demand. ...
A rerouting strategy is designed based on the rerouting behaviour of vehicles when road closure occurs in life, the control parameters include the control of the CAV's automatic rerouting period, rerouting probability, HDV Knowledge of the time of lane closure, as well as their rerouting probability. The aim of this study is to find the optimal combination of these five parameters. Four levels of CAV penetration (20\%, 40\%, 60\%, and 80\%) are considered with the objective of minimizing the total travel time on a mixed CAV and human-driven vehicle (HDV) traffic flow network. The main question is \textbf{What is the optimal rerouting strategy for CAV and HDV mixed traffic when road closure happens?} and in the process of answering this question, the effects of CAV penetration, individual rerouting parameters and different road closure locations are considered and analyzed.
In this thesis, a simulation-based approach is used to model the traffic flow applying both micro and meso scale models. Then, the simulation is conducted for the predefined scenarios, then the sensitivity analysis of each relevant parameter is performed using a one-factor-at-a-time approach to understand the impact of each parameter on the network traffic condition. Finally, Bayesian optimisation is used to find the optimal rerouting strategy within a certain search range and number of times, where the results obtained from the sensitivity analysis are used to determine the parameter search space.
The grid network and the Sioux Falls network are simulated respectively and the relatively optimal rerouting strategies are found for them. The grid network can be regarded as a local area on the network, while the results of Sioux Falls, as a larger network, can provide some basis for city-level traffic management.
The key findings of this thesis include (1) CAV penetration increases bring reductions in TTT and TWT and increase in TTD to the network, overall, the traffic flow movement improves and severe congestion decreases, and network conditions improve significantly during the growth phases of 20\%-40\% and 60\%-80\%; (2) the importance of each rerouting parameter varies for different networks and at different penetration rates, and the results fluctuate significantly between different test values, with no single increasing and decreasing trend; (3) road closures at entrances and exits located at intersections are more critical and require targeted rerouting strategies; the traffic demand distribution has a significant impact on it; (4) Bayesian optimization can find the optimal rerouting strategy in a finite amount of time, where the specific strategy and the improvement effect varies for different networks and levels of demand.
Optimising Bridge Maintenance Planning Considering Hindrance to Road Users
An improved method combining optimisation and simulation applied to the city of Amsterdam
This study aims to optimise the planning of a given set of bridge maintenance projects to reduce hindrance to road users, combining a genetic algorithm with traffic simulations using a new estimation method to improve the assessment of simultaneous closures. The genetic algorithm selects the optimal starting time and execution duration for each bridge while minimising maintenance cost and additional travel times for the modalities car, freight and bicycle. Using the fast static traffic simulation of the Urban Strategy Tool of TNO, a new estimation method for evaluating simultaneous closures is proposed, accounting for interdependencies between bridges. Results of a case study on four urban bridges in Amsterdam show that the new method provides more accurate estimates of additional travel time compared to previous methods and generates better solutions. Moreover, the fast proposed optimisation framework makes it possible to evaluate multiple scenarios in reasonable time to assist in decision making of maintenance planning.
...
This study aims to optimise the planning of a given set of bridge maintenance projects to reduce hindrance to road users, combining a genetic algorithm with traffic simulations using a new estimation method to improve the assessment of simultaneous closures. The genetic algorithm selects the optimal starting time and execution duration for each bridge while minimising maintenance cost and additional travel times for the modalities car, freight and bicycle. Using the fast static traffic simulation of the Urban Strategy Tool of TNO, a new estimation method for evaluating simultaneous closures is proposed, accounting for interdependencies between bridges. Results of a case study on four urban bridges in Amsterdam show that the new method provides more accurate estimates of additional travel time compared to previous methods and generates better solutions. Moreover, the fast proposed optimisation framework makes it possible to evaluate multiple scenarios in reasonable time to assist in decision making of maintenance planning.