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How To Ensure Safe Transportation Infrastructure

By November 29, 2023 December 26th, 2023 No Comments
Bike Lane

In the United States, a transportation safety crisis is leading to record numbers of fatalities: 38,680 people were killed in motor vehicle crashes in 2020, and by the end of 2021, nearly 43,000 more people had died on U.S. roads, marking a 10.5% overall increase in deaths — and the highest death toll recorded since 2005.

Among these fatalities, about 13% were pedestrians — that’s 7,388 people who died while walking, the highest number recorded in decades.

At the same time, the rate of fatalities per 100 million vehicle miles traveled (VMT) has also worsened, increasing significantly in 2020, likely due to high rates of speeding during early COVID lockdowns that led to empty streets. But this increase held steady in 2021.1

Faced with these fatal statistics, the need for safer roadway infrastructure is clear. To address the problem, transportation professionals must diagnose the factors that make roads so fatal and implement countermeasures that are proven to work. But not every road needs the same safety improvements. So how do you ensure safe transportation infrastructure?

In this post, we’ll examine:

  • What makes public roads safer for various modes of travel
  • The Safe System Approach to transportation safety
  • Ways to improve transportation infrastructure safety
  • The data behind safer infrastructure

What Makes Roads Safe for Each Mode of Travel?

There is no single factor that makes all roads safer or more equitable. Each road and mode of travel may benefit from different types of infrastructure and policy, making a data-informed approach key to effective safety interventions.

It should be acknowledged that non-infrastructural factors — such as vehicle design and driver education — also impact road safety and should be considered as part of a holistic approach to reducing fatalities and injuries on the road.

However, in this article, we’ll focus specifically on transportation infrastructure and road design strategies that boost transportation safety. Below, we’ll explore some of the ways you can make public roads safer for various modes of travel.

Public Transport Safety

Public transport safety has to address a couple of overarching concerns: First, modes of public transportation, like city buses or streetcars, need safe roadways. Second, access points like bus stops must give riders safe ways to wait, embark, and disembark.

riders with masks wait at bus stop

Riders wait at a bus stop with ample seating, good lighting, and textured curb edges that improve accessibility for those with visual impairments.

Road Safety Infrastructure for Public Transport

Bus lanes are one excellent option for improving the safety of public transport. Not only do they improve travel times, but they also give buses a safe lane for stopping without interrupting car traffic. In a 2019 study by the Maryland Department of Transportation, bus lanes reduced bus-involved crashes by 12%.2

Raised medians can also help keep transit users safe from oncoming traffic as they get on and off a public transport vehicle.

Railway crossings are also an essential tool in making roads safer for public rail.

Safer Spaces for Public Transport Users

To make public transit access points safer for riders, these tactics can be helpful:

  • Placing bus stops consistently along routes to make them easier to find.
  • Placing useful crosswalks near transit stops to prevent unsafe crossings.
  • Using apps, mobile webpages, and other methods to reduce wait times and make schedules, route maps, and other important information accessible.3
  • Ensuring that bus stops, stations, and other transit hubs are well lit.
  • Ensuring transit hubs are accessible to people with disabilities, providing ample seating and spaces for wheelchairs, strollers, baby seats, groceries, and so on.
  • Establishing more frequent service to ensure that people don’t have to wait alone at stations or stops.4

Cyclist Safety

Cycling activity boomed during the pandemic, increasing 37% across the U.S. between 2019 and 2022. But many roads are still unsafe for cyclists and in need of safety interventions to ensure increased biking doesn’t result in increased road deaths for these cyclists.

For example, early in the pandemic, Walk Bike Nashville (WBN) heard resident concerns about increased rates of speeding. They analyzed traffic volume and speed, and discovered that motorists took advantage of empty streets to drive much faster. In June 2022, 22% of drivers were traveling 30 mph over the speed limit on one key roadway.

Higher speeds make roadways much more dangerous for both cyclists and pedestrians. Narrowing or removing vehicle lanes, adding bike lanes, and widening sidewalks can help slow travel speeds and make roads safer for cyclists. See our section on road diets below for more details.

Additionally, while bike lanes can improve safety for cyclists by increasing their visibility and giving them dedicated space on the roadway, not all bike lanes are created equal. While an unprotected bike lane is usually better than no bike lane at all, some bike lanes can still leave cyclists in the path of opening car doors, swerving vehicles, or improperly parked cars that block the bike lane entirely.

Bike lanes that are protected from vehicle traffic or dooring by central hatching, raised medians, various types of barriers, or even street art can keep cyclists much safer than unprotected bike lanes.

For example, in Kansas City, a protected bike lane on Armour Road significantly reduced instances of dangerous speeding and more than doubled bike ridership on the road.

armour road travel speed data after road diet

A visualization from StreetLight InSight® of average speed on Armour Road in the 2021 study period shows how the bike lane curtailed speeding. There are very few instances of vehicles traveling above 40 mph (shown in green) when that proportion was much higher before, about one in every 20 trips.

Pedestrian Safety

Unlike bicycling, walking activity has plummeted since the pandemic. An analysis of pedestrian activity in the top 100 U.S. metros and 48 states (excluding Hawaii and Alaska) between 2019 and 2022 revealed declines in every region, ranging from 23 to 49 percent.

Even with these declines, pedestrian road deaths reached a 40-year high in 2022, according to the Governors Highway Safety Association.5

As noted above, safe vehicular speeds are a crucial component of pedestrian and cyclist safety. Speed reduction tactics like road diets (see section below), widening sidewalks, narrowing lanes, and reducing speed limits can have huge positive impacts on pedestrian safety.

Increasing the visibility of pedestrians, especially at intersections, can also dramatically impact pedestrian safety. Tactics like daylighting — where the sides of the road near an intersection are kept free of parked cars and other visual obstructions — ensure drivers can see pedestrians and vice versa, reducing the risk of pedestrians being hit as they cross the street.

Reducing crossing distance also helps keep pedestrians safe by reducing the amount of time spent crossing vehicle lanes. Pedestrian refuges and bulb-outs are common ways to accomplish this goal. Signalized crosswalks and synchronized signal timing are also key to intersection safety for pedestrians.

Vehicle Safety

Many of the tactics explored above also promote vehicle safety. Slower speeds, attentive driving, and smooth traffic flow help keep drivers out of accidents. Reduced speed limits, clear signage, daylighting, and optimized traffic signals are just a few of the tactics discussed above that can also improve these safety factors.

Some additional tactics like rumble strips, median barriers, and roadside design improvements at curves specifically target improved road safety for vehicles.

Rumble strips are milled or raised pavement elements placed along the edge of a travel lane that cause vibration when driven over, alerting drivers when they are veering outside the travel lane.

Median barriers help separate opposing directions of traffic along a roadway, and help avoid head-on collisions on two-way roads.

Horizontal curves account for 27% of all fatal crashes, according to the FHWA.6 Improved signage, clear zones, slope flattening, shoulder widening, and various types of barriers and guardrails can all help improve these dangerous roadway segments. Clear zones and wide shoulders give drivers a safe place to regain control of their vehicle, while barriers and guardrails help keep them from veering off the roadway or into oncoming traffic.

What Is the Safe System Approach to Transportation Safety?

The Safe System Approach is a holistic strategy aimed at reducing road deaths to zero. This approach was originally inspired by the Vision Zero movement, which began in Sweden and has since gained traction across the globe.7

The goal of the Safe System Approach is to make the entire transportation system safer — from roadway infrastructure to vehicle design, driver education, and emergency response — so that no one is killed or injured while using roadways. It recognizes that people make mistakes and vehicles malfunction. Thus, roadways need to be designed in a way that accommodates human and mechanical errors to help prevent crashes, injuries, and fatalities.8

Part of what makes the Safe System Approach effective is that it focuses on making proactive safety improvements. For example, city planners may discover an area that experiences recurring safety issues, and set out to fix those issues. Under a Safe System Approach that relies on proactive safety planning, officials would also be able to flag sites that share the same design as the one experiencing safety challenges. They can then flag these similar areas, making improvements to prevent safety issues before problems arise.9

Illinois traffic calming-measures example from StreetLight's Safety Prioritize tool

StreetLight’s Safety Prioritize tool helps planners and operations managers diagnose safety concerns and identify the best countermeasures based on the most up-to-date mobility data.

Top Ways to Improve Transport Infrastructure Safety for All

Beyond the safety interventions explored above for each mode of travel, there are a few common safety tactics that can benefit all road users. In step with a Safe Systems Approach to road safety, these tactics often achieve holistic changes to how roadways are traversed, rather than addressing safety concerns piecemeal.

Building Complete Streets

The “Complete Streets” approach builds on Safe Systems by focusing on roadway infrastructure that equitably addresses the needs of all road users — not just vehicles. This includes bikers, drivers, public transit users, pedestrians, and even roadside diners.

Just as importantly, the Complete Streets approach also takes into account all ages and abilities. That means designing features for potentially disadvantaged groups like the elderly, people who use wheelchairs or walking aids, or people with hearing and vision impairments.

Thus, most Complete Streets policies include provisions to add bike and bus lanes to roadways so that municipalities can improve safety and access for these modes. For pedestrians, Complete Streets improvements may include curb extensions, audio traffic signals for the vision impaired, safer crosswalk designs, or daylighting.

Road Diets

Road diets are a proven safety solution that can often be implemented at very low cost. In many instances, the only expense is the cost of restriping a roadway.

Roads on a road diet take one or more lanes of general vehicle traffic and transform them into something else: bike or pedestrian lanes, bus lanes, or even central turn lanes that can be used by vehicles traveling in both directions. In some cases, municipalities may also use the space from removed vehicle lanes to install or widen existing medians, sidewalks, or shoulders.

Road diets often work to lower vehicle speeds for improved cyclist and pedestrian safety, or even to promote public transportation options like busing. This often comes with added advantages, like reducing greenhouse gas emissions while creating more walkable spaces—or spaces that are more accessible to underserved populations who rely on public transit.

Temporary road diets can also be created using jersey barriers, traffic cones, or portable pylons — a tactic many cities used during the COVID pandemic to calm traffic. In Waterloo, Ontario, for example, authorities put up black-and-orange construction barrels along 30 kilometers of roadway to convert space previously devoted to vehicles into temporary bike lanes. A study by StreetLight confirmed that the new bike lanes increased bike activity by 39% while reducing vehicle speeds by 12%.

Although proposed road diets often raise concerns that reducing lanes could lead to increased congestion and longer travel times, studies often show that travel times do not significantly increase after the implementation of a road diet.

For example, in 2019, Armour Road in North Kansas City, Missouri underwent a series of improvements, including the addition of a new protected bike lane and pedestrian refuges. A before-and-after study by StreetLight shows a significant reduction in dangerous vehicle speeds, double the biking activity, and a negligible increase in travel times (around five seconds on average) along the corridor.

Armour Road with traffic calming measures

A painted crosswalk along with temporary pylons and traffic cones help calm traffic and protect cyclists on Armour Road in North Kansas City, Missouri.

The Data Behind Safer Transportation Infrastructure

As we’ve explored, there are many ways to promote safer transportation infrastructure — and identifying the best safety interventions for a given intersection, roadway, or community requires a deep understanding of existing conditions and the potential impact of various approaches.

Transportation data like vehicle volumes, bike and pedestrian activity, turning movement counts, vehicle speeds, and more can help transportation professionals choose the right countermeasures, anticipate their impact, and measure before-and-after success.

Planners and engineers often rely on data from permanent traffic counters, manual counts, or surveys to understand existing conditions and anticipate impact — but not all roads have counters installed, and manual counts and surveys can suffer from sample size issues and bias.

Online transportation data analytics can help fill data gaps and avoid putting staff in harm’s way to collect reliable information on how people and vehicles move. The video below shows how DOTs, MPOs, and other agencies can leverage online analytics to perform safety studies and choose the right countermeasures for their region.

For a deeper dive into key safety metrics and how to use them to diagnose dangerous roadways, choose countermeasures, secure funding, and measure success, download our Practitioner’s Guide to Transportation Safety.

1. U.S. Department of Transportation, “The Roadway Safety Problem.” Feburary 2023

2. Maryland Department of Transportation. “Dedicated Bus Lanes Before and After Study.” February 2019

3. Rural Health Information Hub. “Models that Increase Access to Public Transportation.”

4. New York University Rudin Center for Transportation. “The Pink Tax on Mobility: Opportunities for Innovation.” February 2022

5. Governors Highway Safety Association. “Pedestrian Traffic Fatalities by State: 2022 Preliminary Data.” 2023

6. U.S. Department of Transportation Federal Highway Administration. “Roadside Design Improvements at Curves.”

7. U.S. Department of Transportation Federal Highway Administration. “Zero Deaths and Safe System.” August 2023

8. U.S. Department of Transportation Federal Highway Administration. “NHTSA’s Safe System Approach: Educating and Protecting All Road Users.” Winter 2022

9. U.S. Department of Transportation Federal Highway Administration. “The Safe System Approach: How States and Cities Are Saving Lives.” Winter 2022