The year 2017 has seen an alarming rise in vehicle-ramming attacks including, most recently, the attack on heavily-trafficked La Rambla in Barcelona, Spain that resulted in 14 deaths and left at least 130 people injured. City officials and terrorism experts predict that these attacks will continue in the coming years and with the unpredictability of this type of attack, cities must act to protect pedestrians against this new and deadly threat.
In response to these threats, cities have developed creative methods for increasing pedestrian protection, especially in highly crowded public spaces. Because most public spaces need to maintain openness for everyday use, a big challenge for city planners and architects is how to avoid turning city streets into fortresses.
One popular way to enhance security is to disguise bollards as site furnishings like potted plants and seating. Arsenal’s new stadium in London has large concrete block letters spelling out the team’s name outside the stadium’s front entrance. A large pedestrian plaza is located behind the letters, safely shielded from a vehicle treat.
The city of Paris has had success preventing mass casualties from vehicle ramming attacks using a combination of protective strategies. Paris has installed a network waist-high posts at street corners and along many streets within the city. The posts are stylized to look decorative, but spaced close together to prevent a high-speed vehicle attack. Along one of the city’s most popular and pedestrian-trafficked streets, the Champs-Elysees, there is a maze of obstructions between the pedestrian walkway and the busy roadway. Elements of the maze include closely spaced trees, hefty light-posts, portable metal fencing, and advertisement signs.
Other cities like Las Vegas are adding bollards along heavily trafficked areas such as the Las Vegas Strip. Bollards are effective in stopping vehicle ramming, installing them throughout a city is cost-prohibitive. For this reason, bollards often only protect the most high-profile pedestrian-trafficked streets in a city. The 700 bollards Las Vegas will be installing along The Strip are reported to cost a total of $5 million. In order to expand protection to less high-profile areas, cities need a more cost effective and less intrusive way to protect against vehicle ramming.
Transportation planners and engineers have already been developing design concepts to enhance pedestrian safety for accidental vehicle-pedestrian collisions. These concepts center around reducing a vehicle’s maximum achievable speed at intersections and long straight roads. Many of the concepts also increase pedestrian comfort on city streets by adding trees and site furnishings. These same concepts can be applied to protecting pedestrians against vehicle based terrorist attacks. At low vehicle speeds, pedestrians have a much higher chance of surviving or escaping a collision.
On long straight roads, one method of reducing vehicle speed is to narrow the roadway. This can be done by converting a two-lane road to one lane road with adjacent street parking. The street parking provides a physical barrier between vehicles and pedestrians while also narrowing the roadway. This strategy works best at two lane roads where traffic demand is low and a high vehicle speed is achievable. Adding street parking is a low-cost solution, which also provides parking for nearby businesses and residents.
Another way of reducing vehicle speed on long straight roads is to construct curb bump-outs at pedestrian crosswalks. Curb bump-outs increase pedestrian visibility at cross walks during everyday use and narrow the road and introduce an obstacle into an otherwise open roadway. A key feature of curb bump-outs is site furnishings that protect pedestrians from collisions. If curb bump-outs are spaced close together, they can create an obstacle course for vehicles that is very hard to navigate at high speeds. For every-day use, closely spaced bump-outs can be used to discourage vehicle traffic at predominantly pedestrian streets.
A combination of street parking and curb bump-outs is an ideal way to slow traffic and create obstacles at long straight roads. San Francisco is introducing the concept of parklets, which replace two to four street parking spots with a public park that includes seating, plants, and artwork. Parklets narrow the roadway like a curb bump-out and decrease the reliance on having consistently parked cars for protection. For enhanced protection of people in the parklet, the structure of the parklet may be designed to resist vehicle impact using disguised bollards or posts.
At intersections, one way to reduce a vehicle’s speed is to reduce the curb radius at the four corners of the intersection. Many cities have already begun infrastructure revitalization programs to reduce curb radii in heavily-trafficked pedestrian areas. Smaller curb radius forces drivers to make tighter turns and reduce their speed. Decreasing the curb radius also results in a shorter street crossing distance, which decreases pedestrian exposure to vehicles. Reducing a curb radius from 15 feet to 5 feet at a street without street parking decreases the maximum speed of a vehicle from 17 mph to 12 mph.
For example, the following protective strategies can be combined to create safer roadways for pedestrians. On a typical two-lane road, the right-most lane can be converted into street parking zones , curb bump-outs or parklets. The addition of street parking increases the turning radius at intersections, which allows cars to turn at higher speeds. To counteract this increase of turning radius, a curb-bump out can be constructed at the corner of the intersection with a smaller curb radius. For added protection at street corners, posts or bollards can be installed to protect pedestrians from oncoming traffic. The posts do not have to extend past the intersection because the parked cars act as separation between pedestrians and vehicles.
Protection from vehicle-ramming can easily be implemented if the right design steps are taken during an infrastructure revitalization program. As cities allocate money towards upgrading infrastructure, special consideration can be made for adding pedestrian protection from vehicle ramming. Pedestrian protection can come in many different forms and previously overlooked elements such as street geometry and street parking can create more cost-effective solutions than more traditional methods, such as lining the streets with bollards.