Florida, United States
Pedestrian safety engineering and intelligent transportation system-based countermeasures program for reduced pedestrian fatalities, injuries, conflicts and other surrogate measures : Miami-Dade site
Summary Information
This report presents the methods and key findings from Phase II of the Miami-Dade comprehensive pedestrian safety planning and engineering project. It is one of three such projects in the nation funded by the Federal Highway Administration (FHWA) that evaluates the effectiveness of a pedestrian safety plan to target higher-injury areas (Phase I) and the implementation of a range of mostly low-to-moderate-cost, innovative engineering safety improvements (Phase II).
Miami-Dade County has the highest incidence of pedestrian injuries and fatalities in the State of Florida. During the nine years prior to the FHWA project, the Department of Highway Safety and Motor Vehicles (DHSMV) reported a total of 15,472 pedestrian crashes in the Miami-Dade County, which included 670 fatal crashes (4.2 percent).
The Phase I planning analysis and recommendations were developed in 2002 and revised in 2004. Phase II began with extensive engineering efforts in 2005 and 2006. Fifteen countermeasures were implemented by the University of Florida team (nine engineering and six ITS countermeasures). The ITS countermeasures were:
- ITS video pedestrian detection
- Rectangular LED rapid flash beacons for uncontrolled multilane crosswalks
- ITS smart lighting at crosswalks with nighttime crashes
- ITS "No Right Turn on Red" (NRTOR) Signs
- Pedestrian countdown timers
- Speed trailers
The most important measure was data on crashes because these best validated the safety value of the countermeasures installed. However, because multiple treatments were installed in all corridors it was impossible to attribute the crash reductions to any particular countermeasure. The original plan was to employ a mix of video recording and field observation to record surrogate measures. However, the video recording systems were destroyed by a major hurricane, and therefore field observation substituted the video recording component to assess the effects of each treatment. The shift from video to live data recording required a reduction of the number of items scored from those originally proposed because field observation does not allow multiple viewing of events.
The pedestrian/driver observations employed a mixture of design features. Some experiments were simple before and after installation evaluations. In other cases, multiple baseline (staged introduction of the treatment at different sites to control for extraneous variables) and follow-up observations were conducted to ascertain the effects of the passage of time and novelty fading. In a few cases treatments were introduced, removed and reintroduced using replication logic to rule out the effects of uncontrolled variables. Statistical tests were employed (generally z-tests and t-tests) to test for difference of proportions/means.
Results:
The benefits to the ITS countermeasures are as follows:
- The ITS video pedestrian detection device was placed at a mid-block traffic signal. The camera was reliable (except for joggers and cyclists) but many pedestrians did not wait to cross even when the device placed the call for them. This treatment needs to be used in conjunction with reduced minimum green time.
- The Rectangular LED rapid flash beacons for uncontrolled multilane crosswalks increased the percentage of drivers yielding to pedestrians from 0 percent to 65 percent at one site and from 1 percent to 92 percent at the second site. Both test sites were high-speed multilane roads.
- ITS smart lighting at crosswalks with nighttime crashes was used with the rectangular LED beacon. It was found not to be effective but the level of illumination was not very great.
- ITS "No Right Turn on Red" (NRTOR) sign statistically significantly reduced violations as compared to the static sign and produced a marked decrease in the percentage of drivers turning right on red (ROR) who made no stop from 40 percent to 13 percent.
- The installation of the countdown timers was associated with a statistically significant increase in the percentage of pedestrians that pressed the call button.
- The speed trailer (Portable Changeable Message Speed Limit Signs) increased braking for pedestrians but had no effect on speed which was already within the speed limit.
