Martin Guttenplan

Modeling the Roadside Walking Environment: Pedestrian Level of Service

A method is needed to objectively quantify pedestrians’ perception of safety and comfort in the roadside environment. This quantification, or mathematical relationship, would provide a measure of how well roadways accommodate pedestrian travel. Essentially, it would provide a measure of pedestrian level of service (LOS) within a roadway environment. Such a measure of walking conditions would greatly aid in roadway cross-sectional design and would help evaluate and prioritize the needs of existing roadways for sidewalk retrofit construction. Furthermore, the measure can be used to evaluate traffic-calming strategies and streetscape designs for their effectiveness in improving the pedestrian environment. Such a measure would make it possible to merge pedestrian facility programming into the mainstream of transportation planning, design, and construction. To meet the need for such a method, as well as to fulfill a state mandate to establish levels of service standards for all transportation modes, the Florida Department of Transportation sponsored the development of the Pedestrian LOS Model. The model was developed through a stepwise multivariable regression analysis of 1,250 observations from an event that placed 75 people on a roadway walking course in the Pensacola, Florida, metropolitan area. The Pedestrian LOS Model incorporates the statistically significant roadway and traffic variables that describe pedestrians’ perception of safety or comfort in the roadway environment between intersections. It is similar in approach to methods used to assess automobile operators’ level of service established in the Highway Capacity Manual.

Intersection Level of Service for the Bicycle Through Movement

The Florida Department of Transportation (DOT) has initiated multi-modal level-of-service (LOS) methodologies, including that for the bicycle travel mode. It has already adopted a bicycle LOS methodology for the roadway segment portion of the transportation network, the Bicycle Level of Service Model. Florida DOT’s ultimate goal is to develop corridor- and facilities-level LOS methodologies. Toward that goal, Florida DOT sponsored research to develop the first part of an intersection bicycle LOS methodology, the Intersection LOS for the bicycle through movement. This Intersection LOS for the bicycle through movement would provide a measure of the level of safety and comfort experienced by bicyclists riding through an intersection. The Intersection LOS model for the bicycle through movement is based on Pearson correlation analyses and stepwise regression modeling of approximately 1,000 combined real-time perceptions from bicyclists traveling a course through a typical U.S. metropolitan area’s signalized intersections. The study’s participants represented a cross section of age, gender, and geographic origin of the population of cyclists. Although further hypothesis testing is being conducted, the resulting general model for the Intersection LOS for the bicycle through movement is highly reliable, has a high correlation coefficient (R2 = 0.83) with the average observations, and is transferable to the vast majority of U.S. metropolitan areas. The study reveals that roadway traffic volume, total width of the outside through lane, and the intersection (cross street) crossing distance are primary factors in the Intersection LOS for the bicycle through movement.

WHY PEOPLE CROSS WHERE THEY DO: THE ROLE OF STREET ENVIRONMENT

The role of the street environment in the way people cross roads in urban settings is modeled. Respondents were placed in real traffic conditions at the curbside of street blocks in the Tampa Bay, Florida, area for 3-min observations of the street environments. Without crossing the blocks, respondents stated their crossing preference at each of six blocks. The origin and destination of each crossing were hypothetically set and varied across the blocks. So were the options available: two options for crossing at an intersection and up to four options for crossing at midblock locations. Within the framework of discrete choice models, the stated preferences are explained with the street environment, including traffic conditions, roadway characteristics, and signal-control characteristics. All three components of the street environment are considered: midblock locations, intersections, and roadside environment. The data are described; a nested logit model of pedestrian street-crossing behavior is estimated; and its implications to researchers and practitioners are discussed.

Crossing Locations, Light Conditions, and Pedestrian Injury Severity

This paper assesses the role of crossing locations and light conditions in the severity of pedestrian injuries through a multivariate regression analysis to control for many other factors that also may influence pedestrian injury severity. Crossing locations include midblock and intersections, and light conditions include daylight, dark with street lighting, and dark without street lighting. The paper formulates a theoretical framework on the determinants of pedestrian injury severity and specifies an empirical model accordingly. The paper applies the ordered probit model to the KABCO severity scale of pedestrian injuries that occurred while attempting street crossing in the years 1986-2003 in Florida. In terms of crossing locations, the probability of a pedestrian dying when struck by a vehicle is higher at midblock locations than at intersections for any light condition. The odds of sustaining a fatal injury are 49% lower at intersections than at midblock locations under daylight conditions, 24% lower under dark-with-street-lighting conditions, and 5% lower under dark-without-street-lighting conditions. Relative to dark conditions without street lighting, daylight reduces the odds of a fatal injury by 75% at midblock locations and by 83% at intersections, whereas street lighting reduces the odds by 42% at midblock locations and by 54% at intersections.

Level-of-service model for pedestrians at signalized intersections

This paper documents a study performed to develop a level-of-service (LOS) model that accurately represents pedestrians’ perceptions of crossings at signalized intersections. This model incorporates perceived safety and comfort (i.e., perceived exposure and conflicts) and operations (i.e., delay and signalization). Data for the model were obtained from an innovative Walk for Science field data collection event and video simulations. The data consist of (a) participants’ perceptions of safety, comfort, and operations as they walk through selected signalized intersections and (b) the design and operational characteristics of these intersections. The resulting model provides a measure of the pedestrians perspective on how well an intersections geometric and operational characteristics meets his or her needs. The pedestrian LOS model for intersections described in this paper is based on Pearson correlation analyses and stepwise regression modeling of approximately 800 combined real-time perceptions (observations) from pedestrians walking a course through signalized intersections in a typical U.S. metropolitan area. The resulting general model for the pedestrian LOS at intersections is highly reliable, has a high correlation coefficient (R2 = .73) with the average observations, and is transferable to the majority of metropolitan areas in the United States. Primary factors in the pedestrian LOS model for intersections include right-turn-on-red volumes for the street being crossed, permissive left turns from the street parallel to the crosswalk motor vehicle volume on the street being crossed, midblock 85th percentile speed of the vehicles on the street being crossed, number of lanes being crossed, pedestrians delay, and presence or absence of right-turn channelization islands.

Multimodal Level-of-Service Analysis at Planning Level

Methods of determining the level of service (LOS) to scheduled fixed-route bus users, pedestrians, and bicyclists on arterials and through vehicles are presented. The research is based on LOS research for the individual modes and uses a comprehensive arterial approach based on research conducted in Florida. The Florida Department of Transportation (FDOT) developed a multimodal LOS analysis process to measure and provide mobility for diverse roadway users. In 1999 the Florida legislature authorized creation of multimodal transportation districts. It also directed FDOT to develop methods for the measurement of performances of various transportation modes to assist local governments with concurrency requirements for growth management. The Highway Capacity Manual’s (HCM) assessment of arterial LOS does not describe the quality of transportation service provided by the facility as much as it describes the quality of service provided to the through vehicle (automobile) users on the facility. Although this concept does address the primary mode of travel, it does not address the service that the arterial provides to other major potential modes (e.g., transit, walking, bicycling) or allow a multimodal LOS analysis. In the 2000 HCM, LOSs for pedestrians and bicyclists are essentially based on how crowded the respective modal facilities are. However, recent research on quality of service for pedestrians and bicyclists indicates that the most important factors are the lateral separation of the mode and motorized vehicle volume, speed, and type and frequency of transit service. FDOT’s research has applied these models with planning-level assumptions.

PLANNING-LEVEL AREAWIDE MULTIMODAL LEVEL-OF-SERVICE ANALYSIS: PERFORMANCE MEASURES FOR CONGESTION MANAGEMENT

The state of Florida has been experiencing an explosion of growth, and it is one of the fastest growing states in the country. While the state has been in the forefront of growth management initiatives, the results have been less than satisfactory. The state recognized the need to integrate land use planning efforts with transportation planning efforts. Legislation was passed that allows the formation of multimodal transportation districts, which focus on appropriate land use mixes and densities that would enhance the use of transportation modes other than the automobile. There are several key elements in the evaluation of these districts, using both land use analysis and the recently adopted multimodal level-of-service performance measures. To validate these evaluation techniques, especially focusing on the level-of-service performance measures, several case studies were undertaken. The guidelines for the formation of a multimodal transportation district provide local governments with a template for enhancing existing and new development. These guidelines also provide a blueprint for sustainable growth and the promotion and development of livable communities through the integration of transportation, land use, and urban design.

MULTIMODAL CORRIDOR LEVEL-OF-SERVICE ANALYSIS

The 2000 release of the Highway Capacity Manual (HCM) provides for the first time a corridor analysis method that guides users in the application of various chapters of the HCM to the analysis of automobiles and transit in a corridor. Together with the recent publication of the Transit Capacity and Quality of Service Manual (TCQSM), the HCM 2000 represents a significant advance in the direction of multimodal level-of-service (LOS) analysis. However, relatively little guidance is given in either the HCM or the TCQSM on the compilation of automobile and transit segment levels of service into a measure of corridor level of service. In addition, bicycles and pedestrians are ignored in the corridor methodology. A methodology was developed and tested in Florida for measuring and reporting the user-perceived quality of service for highway corridors from a multimodal perspective. Automobile and transit LOS analyses are based on the HCM 2000 and TCQSM, respectively. Bicycle and pedestrian levels of service are based on the bicycle and pedestrian LOS models, respectively. Four classes of corridors are recommended, and the methodology was tested on two classes of urban corridors, with and without a freeway. The methodology is applied in three steps: (a) corridor definition, (b) computation of modal level of service, and (c) reporting of results. The methodology was applied to six case studies throughout Florida at generalized and conceptual planning levels. Conclusions about the methodology were drawn from the case studies; the main conclusion is that the methodology provided a reliable overall indicator of corridor level of service by mode.