Modeling

Multimodal Transport Modeling for Nairobi, Kenya: Insights and Recommendations with an Evidence-Based Model

Gonzales, Eric J.
Chavis, Celeste
Li, Yuwei
Daganzo, Carlos F.
2009

Traffic congestion is a growing problem in Nairobi, Kenya, resulting from rapidly increasing population and the crowding of motorized traffic onto a limited street network. This report includes analysis of the traffic conditions in Nairobi, the expected effects of further growth in demand, and a set of recommendations for how to improve the performance of the street network. Data describing motorized vehicle traffic was used to build a simulation model of Nairobi’s street network considering cars and matatus. This model was used to analyze traffic conditions at the city-scale under...

Space Syntax: An Innovative Pedestrian Volume Modeling Tool for Pedestrian Safety

Raford, Noah
Ragland, David R.
2003

This paper describes an innovative pedestrian modeling technique known as Space Syntax, which was used to create estimates of pedestrian volumes for the city of Oakland, California. These estimates were used to calculate pedestrian exposure rates and to create a Relative Risk Index for the city’s first pedestrian master plan. A major challenge facing planners, transportation engineers, and pedestrian-safety advocates is the lack of detailed and high quality pedestrian-exposure data. Exposure is defined as the rate of contact with a potentially harmful agent or event. Pedestrian exposure is...

Pedestrian Volume Modeling for Traffic Safety and Exposure Analysis: The Case of Boston, Massachusetts

Raford, Noah
Ragland, David
2006

This paper examines three types of pedestrian volume models in light of their usefulness for estimating pedestrian exposure for pedestrian safety research. The need for pedestrian flow data as part of pedestrian exposure and safety analysis is outlined, and the background of each type of model is discussed. It then selects the space syntax network analysis model to estimate pedestrian volumes for the city of Boston, Massachusetts. It was found that the model was able to accurately predict pedestrian flows (r-squared 0.81, p-value < 0.0001) after incorporating distance to transit...

The relative vulnerability index: a framework for evaluating multimodal traffic safety

Grembek, Offer
2012

The multimodal transportation network includes a mix of inherently different modes. In addition to differences in price, range, and comfort of travel, these modes differ in mass and velocity, which correspond to different orders of magnitude in the kinetic energy carried. This discrepancy in kinetic energy affects both the level of protection of each mode, and the level of damage it can inflict on users of other modes. Unfortunately, accounting for both sides of a crash is often overlooked. While the quantities and variables of collected data continue to increase, the analyses conducted...

Development and Application of the San Francisco Pedestrian Intersection Volume Model

Schneider, Robert J.
Henry, Todd
Mitman, Meghan F.
Stonehill, Laura
Koehler, Jesse
2013

The San Francisco pedestrian volume modeling process refined the methodology used to develop previous intersection-based models and incorporated variables that were tailored to estimate walking activity in the local urban context. The methodology included two main steps. First, manual and automated pedestrian counts were taken at a sample of 50 study intersections with a variety of characteristics. A series of factor adjustments were applied to produce an annual pedestrian crossing estimate at each intersection. Second, log-linear regression modeling was used to identify statistically-...

A Pilot Model for Estimating Pedestrian Intersection Crossing Volumes

Schneider, Robert J.
Arnold, Lindsay S.
Ragland, David R.
2008

Better data on pedestrian volumes are needed to improve the safety, comfort, and convenience of pedestrian movement. This requires more carefully-developed methodologies for counting pedestrians as well as improved methods of modeling pedestrian volumes. This paper describes the methodology used to create a simple, pilot model of pedestrian intersection crossing volumes in Alameda County, CA. The model is based on weekly pedestrian volumes at a sample of 50 intersections with a wide variety of surrounding land uses, transportation system attributes, and neighborhood socioeconomic...

Effectiveness of a Commercially Available Automated Pedestrian Counting Device in Urban Environments: Comparison with Manual Counts

Greene-Roesel, Ryan
Diogenes, Mara Chagas
Ragland, David R.
Lindau, Luis Antonio
2008

High-quality continuous counts of pedestrian volume are necessary to evaluate the effects of pedestrian infrastructure investments and to improve pedestrian volume modeling. Automated pedestrian counting devices can meet the need for continuous counts of pedestrian volume and reduce the labor cost associated with manual pedestrian counting and data entry. However, most existing automated pedestrian devices are not well suited to the task of counting pedestrians in outdoor environments, and little is known about their effectiveness and accuracy. This study addresses the lack of performance...

Impact of Traffic States on Freeway Collision Frequency

Yeo, Hwasoon
Jang, Kitae
Skabardonis, Alexander
2010

Freeway collisions are thought to be affected by traffic states. To reduce the number of collisions, the study to reveal how the traffic states influence collisions are required. Therefore, the purpose of the paper is to suggest a method to relate traffic states to collision frequency in freeway. We first defined section- based traffic phases showing traffic state of a section using upstream and downstream traffic states: free flow (FF), back of queue (BQ), bottleneck front (BN) and congestion (CT). Secondly, by integrating freeway collision data and traffic data from the California PeMS...

Estimating Pedestrian Accident Exposure: Approaches to a Statewide Pedestrian Exposure Database

Greene-Roesel, Ryan
Diogenes, Mara Chagas
Ragland, David R.
2007

This report discusses approaches to addressing the need for better and more widely available pedestrian volume data in the state of California. While a variety of approaches could be used, this report focuses on the strategy of a statewide pedestrian volume database. This database would meet a variety of data needs for different stakeholder groups. One of its principal purposes would be to allow safety professionals at the state and local levels to estimate pedestrian exposure to risk at specific sites. Since exposure data is essentially equivalent to facility usage data, a pedestrian...

Evaluating the Public Perception of a Feebate Policy in California through the Estimation and Cross-Validation of an Ordinal Regression Model

Martin, Elliot, PhD
Shaheen, Susan, PhD
Lipman, Timothy
Camel, Madonna
2014

Understanding the roots of policy perception can be critical for informing the design and implementation of innovative public policies; Feebates is one such innovative policy and in the context of new vehicles can be designed to offer buyers a rebate for the purchase of low-emission vehicles and a fee for the purchase of high-emission vehicles; Because feebates is a policy that directly impacts the consumer, understanding the dynamics of public perception, support, and opposition is important; This study explores the public perception of a feebate policy within California and evaluates the...