Safety impacts of platform tram stops on pedestrians in mixed traffic operation: A comparison group before–after crash study

Highlights

• The pedestrian safety benefit of platform tram stops was investigated.

• The comparison group before–after crash analysis technique was adopted.

• The results showed a 43% reduction in pedestrian-involved all injury crashes.

• A modified analysis was conducted to control for ridership differences at sites.

• The analysis showed an 81% reduction in pedestrian-involved all injury crashes.

• Also an 86% reduction in pedestrian-involved FSI crashes was revealed.

Abstract

Tram stops in mixed traffic environments present a variety of safety, accessibility and transport efficiency challenges. In Melbourne, Australia the hundred year-old electric tram system is progressively being modernized to improve passenger accessibility. Platform stops, incorporating raised platforms for level entry into low floor trams, are being retro-fitted system-wide to replace older design stops. The aim of this study was to investigate the safety impacts of platform stops over older design stops (i.e. Melbourne safety zone tram stops) on pedestrians in the context of mixed traffic tram operation in Melbourne, using an advanced before–after crash analysis approach, the comparison group (CG) method. The CG method evaluates safety impacts by taking into account the general trends in safety and the unobserved factors at treatment and comparison sites that can alter the outcomes of a simple before–after analysis. The results showed that pedestrian-involved all injury crashes reduced by 43% after platform stop installation. This paper also explores a concern that the conventional CG method might underestimate safety impacts as a result of large differences in passenger stop use between treatment and comparison sites, suggesting differences in crash risk exposure. To adjust for this, a modified analysis explored crash rates (crash counts per 10,000 stop passengers) for each site. The adjusted results suggested greater reductions in pedestrian-involved crashes after platform stop installation: an 81% reduction in pedestrian-involved all injury crashes and 86% reduction in pedestrian-involved FSI crashes, both are significant at the 95% level. Overall, the results suggest that platform stops have considerable safety benefits for pedestrians. Implications for policy and areas for future research are explored.

Introduction

Public transit, including light rail transit systems, is becoming more important as mobility, accessibility, and environmental problems are becoming of greater concern in many cities around the world. Trams/streetcars are light rail transit vehicles operating on tracks located in the center lane of the road with general road traffic often using all road lanes including the center lane. Tram operation in such condition is often termed as ‘mixed traffic tram/streetcar operation’ and this type of tram right-of-way (ROW) is classified as ‘Category C type ROW’ (Vuchic, 1981).

Safety is a major concern in the design, operation and development of light rail system, especially tram or streetcar systems. Several studies have identified safety concerns for tram systems specially at tram stops under mixed traffic operation as trams, cars, and pedestrians share the same roadway (Korve et al., 1995, Currie and Shalaby, 2007, Korve and Siques, 2000, Naznin et al., 2015). At older type tram stops (e.g. curbside stops, safety zone stops) in mixed traffic conditions, passengers must cross curbside road traffic lanes to access and egress from trams and collisions between general traffic and passengers often take place as a result of such pedestrian movements (Currie and Reynolds, 2010, Association of German Transport, 2000). Platform tram stops are being constructed progressively to replace older design stops (e.g. safety zone stops) to improve disability access and safety for tram passengers in many countries (Currie and Smith, 2006, Toronto Transit Commission, 2003).

Several countries in the world have light rail transit operation systems. However, light rail vehicles operating in a mixed traffic environment are less common. In the USA, only 15% of total tram track length is in mixed traffic, yet more than 90% of light rail transit crashes occur along the mixed traffic ROW (Korve et al., 1995, Currie and Smith, 2006). In most cases, streetcar tracks run in the center of two-by-two lanes of undivided roads and stops are operated without platforms. These stops have been identified as a major safety concern for pedestrians (Korve and Siques, 2000). UK light rail systems have a greater share of mixed-traffic tram operations compared to USA (e.g. Sheffield has a share of 60%, whereas Germany has around 29%) (Department of Transport, 2011, South Yorkshire Passenger Transport Executive, 2004, Association of German Transport, 2000, Currie and Smith, 2006). Tram stops in mixed traffic condition are entirely based on curbside platform stops. Passengers moving to and from the stops from the footpath are exposed to a considerable degree of risk. Toronto, Canada, has a large share (89%) of mixed traffic operations on its light rail system with a length of 71 km (Currie and Shalaby, 2007). Some platform stops are provided in the middle of the roads beside the tram tracks where roads are wide enough, although many stops are still at the curbside. The safety and accessibility of these stops is a major concern for the Toronto Transit Commission (TTC), which is planning to make all the stops accessible by 2025 (Toronto Transit Commission, 2003). UK and American cities have implemented several countermeasures at streetcar stops to improve passenger safety. For example, a signal-controlled stop system, where passengers wait at the curbside until a streetcar arrives, accessing the streetcar via a dedicated pedestrian signal light. In addition, raised curbside traffic lanes and the provision of a platform by narrowing the road to a single lane in each direction are other measures that are being adopted (Association of German Transport, 2000, Toronto Transit Commission, 2003, Currie and Smith, 2006).

Melbourne, Australia has the largest light rail system in the world with 29 routes and 250 km of track length. Around two-thirds (67%) of the system, with a length of 167 km, operates in a mixed traffic environment, with this share being very large by world standards (Currie and Shalaby, 2007, Currie and Smith, 2006). Currently there are more than 1700 tram stops on the Melbourne tram network (Yarra Trams, 2015), with 80% of these being curbside and safety zone stops with a number of associated safety concerns (Currie and Reynolds, 2010, Public Transport and Victoria, 2014b). Currie and Reynolds (2010) identified that 82% of incidents at tram stops are related to car-pedestrian conflicts. In addition, both curbside and safety zone stops are identified as presenting issues for passengers with disabilities. The Disability Discrimination Act (DDA) of Australia requires conversion of all transit system infrastructure to a fully accessible state within the 20 years from 2002 (DDA, 1992). Consequently, safety zone stops are now progressively being converted to platform stops (Yarra Trams, 2014). Currently, the Melbourne light rail and tram system has platform stops at 139 locations with 374 sets of individual platforms (Yarra Trams Database, 2014). Fig. 1 shows the typical layouts of safety zone and platform tram stops in Melbourne.

Safety zone stops are the prevailing older type stops in central area of Melbourne. These stops comprise a distinctive yellow ‘safety zone’ traffic island (Fig. 1a). Passengers wait along a small narrow strip adjacent to the tracks in the middle of the road with metal railing barriers separating them from passing road vehicles (Fig. 1c and e). These stops are known to have serious crash risks, with the most common type of crash being pedestrian collisions with trams within the narrow waiting area. In addition, there are often gaps between the metal railing barriers (Fig. 1e) and collisions between cars and passengers may occur when passengers try to access the stops through these gaps, crossing unprotected traffic lanes (Currie and Reynolds, 2010).

Platform stops improve this situation through the provision of passengers platforms raised to the level of low floor trams next to the tracks in the middle of the road (Fig. 1b). Passengers access the platform using signal controlled pedestrian crossings. On roads with lower traffic levels, platforms are accessed via zebra crossings at the ends of the platform (Fig. 1d). Currie and Reynolds (2010) evaluated the safety effectiveness of platform stops with a simple before–after crash rate analysis, identified a reduction in car-pedestrian collisions of 62% after platform stop installation. They also conducted a formal safety audit and suggested that the platform stops had reduced ‘intolerable’ crash risks compared to the older stops (safety zone and curbside stops). A recent study by Richmond et al. (2014) identified a reduction in pedestrian collisions due to the introduction of platform stops in Toronto, Canada. It was hypothesized that due to the presence of station barriers, platform stops are only accessible by passengers at signal controlled intersections. This limits the efficacy for pedestrians’ mid-block access, but helps to reduce car-pedestrian collisions. However, these studies conducted only simple before–after crash comparisons and did not consider changes in crash influencing factors such as changes in traffic or pedestrian volume.

Overall, it is clear from the above discussion that pedestrian safety is a major concern at tram stops with previous studies demonstrating improved pedestrian safety at platform stops using the simple before–after crash comparison method. Advanced before–after analysis techniques were not adopted that can examine safety impacts more accurately by considering all influencing factors (e.g. traffic volume) and general trends in safety. Clearly, this is a field worthy for further research.

The aim of this study is to better evaluate pedestrian safety at platform stops through the adoption of a more advanced before–after crash analysis method, the comparison group (CG) method. In addition, a modified crash analysis will be conducted to consider differences in passenger volume between new and older design stops, aiming to test the effect of passenger exposure on safety impacts. This paper is structured as follows: a brief introduction of the methodology employed followed by the data sources for this study. Results are presented with discussions followed by conclusions.