With the increase of multimodal road users, the demand for detection to understand the entire mix of traffic, including vulnerable road users such as bicycles and pedestrians, has increased. From 2010 to 2019, the number of pedestrian fatalities in the U.S. increased by 46% – from 4,302 deaths to an estimated 6,301 deaths, according to the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System.
Video detection technology was once used only to provide input to a traffic signal controller that a vehicle was on the approach, but it can now also provide pedestrian data. But with video detection technology now being able to discern that a pedestrian is in the crosswalk, how does that information become useful to help a traffic engineer understand how pedestrians are using the intersection?
I will explore two components to answer this question: 1) how many pedestrians are using the intersection, and 2) the crossing behaviors at each crosswalk.
Understanding pedestrian crossing counts
With advanced detection systems such as Iteris’ Vantage family of video detection sensors, traffic engineers can detect individual pedestrians in the crosswalk and view pedestrian counts in the VantageLive! Intersection traffic intelligence software. These are hourly counts that separate the direction of travel of pedestrians through the crosswalk, which provide traffic engineers with two key statistics: which intersections have the largest volumes of pedestrians and the peak pedestrian usage times at each intersection (see Figure 1).
Figure 1 - Pedestrian counts and direction in VantageLive!
Understanding pedestrian crossing behaviors
Along with knowing the number of pedestrians, understanding how pedestrians are utilizing the crosswalk with respect to the pedestrian clearance interval timing can help traffic engineers improve intersection safety. Iteris video detection sensors can send an output to the controller when a pedestrian is in the crosswalk.
In addition, by combining detection information with controller events, the signal performance measures capabilities of Iteris’ ClearGuide charts pedestrian crosswalk activity from the time of a pedestrian actuation through the end of the pedestrian clearance interval.
Four insights from ClearGuide’s Pedestrian Activity visualization chart
Visualizing and understanding pedestrian crosswalk usage can uncover several factors affecting intersection safety.
In the chart below, the zero point on the x-axis represents when the pedestrian push button actuation is received by the controller (or start of Walk if the ped is non-actuated). The gray bar represents the time until the start of Walk (blue). The black line represents when the pedestrian(s) was in the crosswalk.
Figure 2 - Pedestrian Activity visualization chart in ClearGuide.
Here is what we can derive from visualizing the data:
If pedestrians are clearing the crosswalk before the end of Flashing Don’t Walk, it can be determined whether or not the pedestrian timing is adequate.
If pedestrians are consistently in the crosswalk after the end of the pedestrian interval, the pedestrian clearance time may not be adequate for the mix of pedestrians at the intersection. A longer Flashing Don't Walk time could be considered to prevent a vehicle-to-pedestrian collision and improve intersection safety for slower-moving pedestrians.
If a high number of pedestrians are in the crosswalk outside of the pedestrian interval, there is an increased risk of a vehicle-to-pedestrian collision because the pedestrian is not protected with the signal timing. This is an enforcement issue. The number of “violators” (i.e., pedestrians who enter and clear the crosswalk during no part of the pedestrian interval) is summarized for the plan at the top of the chart. Pedestrians who push the button and then cross before the Walk signal are shown as a black line during the gray bar.
Vehicles turning through the crosswalk during the pedestrian interval also increase the chance of a vehicle-to-pedestrian collision. Conflicting vehicles and whether they made a right turn or left turn to cross the crosswalk are displayed. Where there is a high rate of right-turn vehicles in the crosswalk at the beginning of the pedestrian interval, implementing an advance pedestrian timing could help to reduce the chance of a vehicle-pedestrian collision.
The Bottom Line
Understanding how pedestrians are utilizing the intersection is pivotal to improve safety at the intersection either through appropriate pedestrian times or recognizing the need for increased enforcement. Controller features such as an advanced pedestrian interval are useful tools for increasing safety when used appropriately.
Transportation agencies interested in implementing life-saving detection and analytics technologies to improve pedestrian safety should consider the following combination of solutions:
- Video detection: Iteris Vantage Video detection is recommended to provide pedestrian data.
- Iteris’ VantageLive! analytics software: Directional pedestrian and bike counts are shown as well as vehicle counts at the intersection to help prioritize multimodal signal timing efforts.
- Iteris’ ClearGuide SPM module: The Pedestrian Activity chart is useful for deciding which safety measures to implement and then to judge the effectiveness of measures taken to increase pedestrian safety.
About the Author:
Allison Palumbo, P.E. is senior engineer planner, Advanced Sensor Technologies at Iteris.
Connect with Allison on LinkedIn.