Engineers have a lot of options in how they design our streets and roads, how safe they make them, who they serve well and who they serve poorly. This post will examine why road design is so important, its underlying philosophy and, finally, some specific design options and why various elements are important. A future article will look at crossings and junction design.
Perspective
When it comes to safe roads, we (the United States) come in last. We have the most dangerous road system of all developed countries with the highest fatality, crash and severe-injury rates. Drivers in the United States kill three to five times as many people per capita as drivers in Europe. That is unconscionable.
Some people say we are simply worse drivers, which may be somewhat true. But traffic engineers elsewhere point to more equitable and effective road design elements in their countries that result in less than one-fourth the fatality, crash and injury rates.
We are also the most overweight and obese population, and according to some measures, the least healthy overall.
Our life expectancy is near the bottom as well — a result of our poor health and high road fatality rates, among other factors. Having the world’s best healthcare is all that saves us from being dead last.
Daily activity is a key to other countries’ better health and life expectancy, primarily due to active transportation such as walking and bicycling. Unfortunately, bad road design in the United States makes multimodal activity more difficult and dangerous. Poor road design affects more than our high rate of road deaths. It also impacts our health.
Design Philosophy
In talking with traffic engineers in the United States and elsewhere, such as the European Union, some key differences in philosophy emerge. At the top is this:
- U.S. Engineers: Drivers can and should drive perfectly, paying full attention at all times and perfectly obeying all rules. Our roads are designed with this expectation.
- EU Engineers: Drivers are imperfect and will make mistakes. Roads must be designed to encourage drivers to pay attention, enforce obedience where possible and mitigate harm as much as possible when mistakes are made. At the core of Dutch design and increasingly elsewhere is sustainable safety.
The vast majority of people killed or severely injured are due to driver error. Nearly half of bicycle riders killed are hit from behind by drivers swerving over the white line between the driving lane and shoulder or bike lane. Dutch/European CROW designs mitigate these.
Other differences:
- U.S.: Level of service (low delay for drivers) is most critical. EU: Safety and human life is most critical.
- U.S.: Speed limits. EU: Target design speeds. When EU engineers want people to drive 30 miles per hour (MPH), they design the road so that people drive that speed and pay close attention while doing so. U.S. engineers rely on the goodwill of drivers and law enforcement. Judging by posts on NextDoor.com about speeding through neighborhoods, this isn’t a winning strategy.
- EU: As little pavement as possible (pavement is expensive, creates noise, creates water percolation problems and encourages inattentive high-speed driving).
- U.S.: Core design constituent: drivers. EU: Core design constituent: all users, with emphasis on the most vulnerable.
- U.S.: Design focuses from the center out, with cars first and then the rest if room and budget allow. EU: Holistic design from the outside in. Safety and comfort for all users is equally important, though safety for the most vulnerable — children and elderly walking or riding bicycles — is paramount.
- EU: Investigate every fatal crash, often with traffic engineers on site. Focus future designs on improved safety. U.S.: Obtain statistics, heat maps and crash reports from law enforcement. Seeing these crashes directly not only is more informative but also has an impact on EU traffic engineers that helps to ingrain a “humans first” priority in their designs.
- U.S.: New maneuver/signal/design allowed if it resulted in only a minimal increase in accidents. EU: New maneuver/signal/design allowed only if it resulted in no increase in crashes/deaths/injuries.
- EU: Strongly encourage walking, bicycle and transit (health, lower congestion, lower cost). U.S.: Encourage people to drive cars for all trips regardless of how short the distance.
Designs
The following designs are in order from least safe to most safe. Click on the design for a larger view.
Ramsey County Typical
This is the basic roadway that Ramsey County has built for several decades. There is no safe place to walk or bicycle. The shoulder is sometimes also called the Curb Reaction Distance (even when no curb exists). Traffic engineers expect that inattentive drivers will veer out of the motor vehicle lane and so no obstructions are allowed in this area so that drivers and their cars will not be harmed.
Here’s a typical Ramsey County road, with 11-foot motor vehicle lanes and 4-plus-foot shoulders. How safe or pleasant an experience is Ramsey County providing for that mom and kids?
Ramsey County New
What’s new? Primarily the name of the Curb Reaction Distance is now Bike Lane. There are two significant concerns with this.
1) Of the bicycle riders killed in the United States each year, about 400 people — or 47 percent — are riding in a shoulder or painted bike lane just like this and are hit from behind by inattentive drivers.
2) Changing the name provides no additional protection. Prior to the name change these engineers expected that inattentive drivers would veer into this area. And often at speeds of 45 to 60 MPH. Why do Ramsey County traffic engineers now think it acceptable for a child or adult to ride a bicycle in this space previously reserved for errant drivers?
There’s more: These lanes become largely unusable much of the year. They are often covered with snow, ice or slush during winter and then covered in road debris much of the rest of the year. More: Do We Really Want Bike Lanes?
Ramsey County is using this design for Edgerton Street in Vadnais Heights, which is being redone this year.
Plus Walkway
This provides at least a safe place for people to walk. It does not provide a safe place for anyone who wants to ride a bicycle.
Two-Way Bikeway
This is what we have along Hodgson Road north of Highway 96, Lexington north of Highway 96 and other roads in Shoreview. When low volumes of people are using it this works, though the design has safety issues.
This design has people walking and bicycling in two directions. This is generally forbidden outside of the United States and for good reason. When drivers approach the roadway from a driveway or side street they look to their left because that is the direction from which vehicles, which are a threat to them, are approaching. Drivers often do not look to their right and so do not see bicyclists coming from that direction. Ironically, when I was riding along Hodgson a couple of weeks ago, I was hit by someone pulling out of the Applewood Pointe Senior Home. She looked in my direction and I thought she’d seen me. I was almost past her when she pulled out and clipped my rear wheel, causing me to fall.
At a signalized junction, even a white “OK to cross” may not protect a pedestrian. If an approaching driver is turning right, you cannot safely cross because drivers often are looking neither ahead nor to their right but only to their left for cars that may threaten their ability to turn right-on-red — without stopping to see if someone is in the crossing.
Most countries in Europe and Asia forbid right-on-red turning. It is much too dangerous. And indeed, numerous people in the United States and Minnesota are killed each year by drivers turning right-on-red. What is the trade-off in a few seconds of drivers’ time versus pedestrians’ lives?
A strip of grass between the roadway pavement and bikeway (Hodgson Road, above) provides several benefits:
- Reduces noise from the road for path users and residents.
- Provides a buffer so that road debris does not build up on the bikeway and reduces the chances of being splashed by the wake thrown up by passing cars.
- Is safer since it acts as a more functional reaction zone for drivers and feels safer simply by being a bit farther from fast traffic, and
- Provides for better rain water percolation so that rain makes it to the local aquifers rather than the storm sewer system.
Trees planted in the grassy area enhance the benefits, help the bikeway feel safer, are more pleasant and provide shade on hot summer days.
When a bikeway is directly next to the roadway (Hodgson Road, below), snow, slush and road debris can accumulate, though the curb helps considerably and it is not nearly as bad as a painted bike lane. Road noise is greater for people on the bikeway, who may find it difficult to talk to each other, but also for people in adjacent yards and houses. Road noise equates with the amount of continuous pavement: The less continuous pavement, the lower the noise level.
Note: Outside of the United States, this will be called a Bikeway (or, in some cases, a Cycleway or Cycle Track). That is the internationally accepted term, and I have used it intentionally. In the U.S. this is often called a Shared Use Path or SUP. The term “path” is typically reserved for recreational purposes, however, and so is given less priority or importance than something used for transportation.
I have heard traffic engineers and city employees say, “but it’s just a path” when discussing safety or other improvements. It’s important that, like the rest of the world, we think of these as the transportation corridors they are and give them the same critical attention and design as other transportation corridors.
One-Way Bikeway on Each Side (Better)
This is much safer since people will be approaching road junctions and driveways from the direction that drivers are also looking for approaching cars. Drivers are more likely to see people walking or riding bicycles, and these users are more likely to be able to make eye contact with drivers.
This will also help with congestion and conflicts since at any time about half of users will be on each side — rather than all users on one side. And since most people are traveling in the same direction, it is more efficient with less conflict.
One-Way Bikeway and Walkway on Each Side (Best – CROW/International Standard)
This is what you will typically see in Europe for roads such as Hodgson, Edgerton and most Ramsey County roads. There are several benefits:
- The narrower driving lanes cause drivers to pay closer attention, slows down the faster drivers and results in a much safer road. Note that these lanes would be narrower in Europe but this is the narrowest allowed here.
- This results in much shorter crossing distances (20 feet versus the current 40 feet) and overall safer crossings.
- The design provides separate space for people walking (3 MPH) and people riding bicycles or mobility scooters (10-15 MPH). Homogenization of speed, mass and direction are critical elements of Sustainable Safety.
- The grass directly next to the roadway reduces roadway noise, and the trees between the roadway and bikeway provide extra protection from errant drivers and make the walkways and bikeways more pleasant.
An alternative might be to create a small grass verge between the bikeway and walkway with lights between the two.
This design resolves the final bits — congestion and conflict — and is the standard in many European countries. This design is a key reason why Europe has the road safety record that it does, why so many people walk and bike, and why they are so much healthier.
Conclusion
The first design has been standard in the United States and, in particular, in Ramsey County, Minnesota. The latter is standard in many European countries and becoming standard in others.
The first is responsible for our low rates of active transportation and so partially responsible for our poor health and obesity. The latter is responsible for Europe’s higher rates of active transportation, better health, lower healthcare costs, and lower rates of overweight and obesity.
The first is responsible for our high rates of road fatalities; the latter for their lower rates of fatalities and serious injuries.
The first is bad for people with disabilities; the latter is best in the world for people with disabilities. The first results in people with disabilities being shut-ins; the latter results in their being out and about getting critical activity and social interaction.
The latter will result in improved property values as increasing numbers of people want to live where they can safely walk and bicycle to school, grocery, pharmacy and dinner.
Next we’ll look at junctions and crossings. Until then a great resource is Junction Design.
Note: I have been hoping to post Parts II and III of What Is The Cost/Value Of A Calorie but first wanted to provide some better background information for Part I. Getting approval to provide this information is proving more difficult than I expected so that series is incomplete for now. I’m hoping that one or two studies currently underway will provide the data in a publicly available source.