Safer, Saner Roads by Design


LMRoadDesign 1002

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.

Hodgson Rd Typical ppf12 9

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?

LMMcMenemy2 1000

Ramsey County New

Hodgson Rd Typical New Painted Bike Lane ppf12 9

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.

Hodgson Rd Plus Walkway ppf12 9

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.

Hodgson Rd TwoWay Bikeway ppf12 9

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?

LMRoadDesign 1000

A strip of grass between the roadway pavement and bikeway (Hodgson Road, above) provides several benefits:

  1. Reduces noise from the road for path users and residents.
  2. 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.
  3. 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
  4. 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.

LMRoadDesign 1001

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)

Hodgson Rd OneWay Bikeways ppf12 9

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)

Hodgson Rd CROW Standard ppf12 9

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.

Hodgson Rd CROW Standard MN ppf12 9

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.

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22 Responses to Safer, Saner Roads by Design

  1. Walker Angell
    Walker Angell July 8, 2019 at 9:47 am #

    Two corrections:

    1) The diagram above showing light posts between the bikeway and walkway should have had a slightly wider grass verge. Light posts would not usually be placed as close to the bikeway as I’ve shown.

    2) I think the engineer who referred to the shoulder on Edgerton as a Curb Reaction Zone was incorrect since this shoulder does allow for parking and I do not believe that would be allowed in any Curb Reaction Zone.

  2. Cindy Winter July 8, 2019 at 1:27 pm #

    An excellent over-view. Congratulations to the writer — obviously much time was spent here, resulting in a most thoughtful review.

    I’d love to see these improvements constructed where I live (California) but much of our area is totally built-out with homes and commercial structures and there is simply insufficient space for everybody — often including motorists — to travel safely.

    While it’s certainly essential to have safe roadway design, should we focus more on urban/suburban planning? Encouraging commuters to share rides. Constructing elevated bikeways as part of new architecture?

    Whatever, I’m keeping this article for future reference.

    • Walker Angell
      Walker Angell July 9, 2019 at 7:09 am #

      Thanks Cindy.

      Where space is as tight as you suggest (residential?) the solution is typically a Bicycle Street. These have a maximum speed of 18 MPH, bicycle riders have right-of-way and cars usually may not pass bicycle riders. This results in a street that’s safe and comfortable for bicycle riders and encourages people to ride.

      Rideshare has been tried several times and has never worked. People simply do not like being tied to other people’s schedules. This is true in the U.S. and EU.

  3. Jeffrey Klein July 8, 2019 at 9:47 pm #

    This is a nice summary of engineering philosophies.

    I do want to note, though, in my experiences in Europe they simply don’t build so many roads like these. What is actually the point? They are too slow to really move traffic and too fast to be a place. Where they exist the two-way separated path is the only solution, but I’d love to figure out how to just stop them from existing.

  4. Walker Angell
    Walker Angell July 9, 2019 at 7:45 am #

    Hi Jeffrey, thanks for your comment. This is actually the CROW standard for higher speed two-lane ‘Distributor’ roadways and these are very common in The Netherlands, Denmark, Sweden, Finland and Switzerland where they have been the standard for a good while. This design has recently become the standard in Germany, France and parts of Spain. Other countries are evaluating adoption.

    I’m a bit confused by the rest of your comment but I’ll take a stab.

    The point is a safe road that fits between Local Access / Residential streets and faster higher volume Principle Arterials.

    This design supports speeds of 30-50 MPH. Generally, the more built-up the area the lower the speeds. Most Ramsey County roads are 40-45 MPH so this fits well with these. I don’t think you’d want higher speeds on these roads and much lower doesn’t make sense either.

    Two-way separated paths or bikeways are very rarely built in The Netherlands and nearby countries as they are dangerous and feel dangerous (uncomfortable) for the reasons I outlined above. Other countries are adopting similar views towards them. The exception is along a roadway with very few entrances and where access is not needed on both sides of the roadway.

    France had begun building a two-way bikeway along the med coast such as 98 leading in the St Tropez. They are re-evaluating this due to the problems I outlined above and are considering going to a more CROW approach of one-way bikeways in each side of the roadway.

  5. Brian July 9, 2019 at 7:53 am #

    Outside of rush hour, right turn on red can save a lot more than a few seconds. Turning onto a major highway late at night can mean waiting several minutes. I know many would just turn right anyhow, but I won’t do it. Now, I am not against banning right turn on red because I see the issues in downtown every day.

    I thought I recall seeing a lot of bidirectional bike lanes in videos from the Netherlands. It is a lot easier to bike there because the climate is much more moderate. It rarely drops below freezing. There are, of course, a lot of other reasons why Dutch people bike a lot.

    • Jack July 9, 2019 at 8:15 am #

      I recently had an 8 hour layover in Amsterdam, and I took a bike/boat tour of the city with local guides. I’m not a regular biker, but I thoroughly enjoyed the trip! My tour guides said Amsterdam has more bikes than citizens, and it showed. Amsterdam is also perfect for biking in that there are no hills, unless you count the bridges.

    • Walker Angell
      Walker Angell July 9, 2019 at 10:24 am #

      As to cold and hills…

      https://streets.mn/2015/08/26/its-too-hilly-cold-hot-far-snowy-and-uncultured-to-ride-a-bicycle-here/#lightbox/6/

      In Amsterdam or Groningen when it’s 20°f and snowing there are not many fewer people riding bicycles than when it’s warmer and sunny. I’m there frequently and weather simply doesn’t stop them. Oulu Finland has a climate nearly identical to Minnesota and yet they have a nearly 30% bicycle modal share.

    • Walker Angell
      Walker Angell July 9, 2019 at 10:31 am #

      I think much of the delay issue you bring up may be because we have much longer light cycle times than other countries. Part of this is that we build much larger junctions for any given amount of traffic and part is that we have long clearance times (when all directions are red to give time for cars to clear). A junction in Europe is smaller so there is less time needed for clearance but drivers there also do not run pink lights to the same extent the U.S. drivers do so even less clearance time needed.

      I’ve often wondered if our pink light running problem is because we have such long cycle times? We are also generally much less obedient than European drivers:

      https://streets.mn/2013/09/10/a-wink-and-a-nod-teaching-our-kids-to-be-criminals-part-i/

      https://streets.mn/2013/09/24/a-wink-and-a-nod-beliefs-laws-and-turning-right-on-red-part-ii/

      https://streets.mn/2013/10/08/a-wink-and-a-nod-a-safer-environment-not-just-a-safe-speed/

      • Brian July 9, 2019 at 4:19 pm #

        The highway I am thinking about is Highway 65 specifically with long signal times. The only way the intersections could be narrower is if the center median was removed to narrow the highway. Changing signal times would just make Hwy 65 traffic that much worse.

        I read a lot of Strongtowns and they advocate for highways to move large volumes of fast traffic and having the rest of the roads designed for very slow traffic. Hwy 65 is a good example of a road that should carry large volumes of high speed traffic.

        I suspect a lot of the opposition to no right on red is a societal problem. As a society we are so busy that drivers feel they need to do dangerous things like turn right on red or go through a light that just turns red to save a minute or two.

        I looked at a map of a Dutch city and they have controlled access highways just like we do ringing the city.

    • Adam Miller
      Adam Miller July 9, 2019 at 10:32 am #

      Dutch people bike a lot because they made it easier to bike than anything else.

    • Walker Angell
      Walker Angell July 9, 2019 at 11:38 am #

      I was just reminded of this right-on-red post: https://streets.mn/2017/11/13/almost-killed-twice/

      I wonder how U.S. traffic engineers and politicians value a human life? Clearly much lower than traffic engineers in all other developed countries?

      • Monte Castleman July 9, 2019 at 5:27 pm #

        So if we actually value human life, lets’ not look red herrings like right turn on red and look at things that will actually improve safety? Or things that won’t produce an incredible backlash from the motoring public, stymieing future safety initiatives that will actually do something? And getting the “safety minded” politicians that initiated it voted out of office in favor of non-safety minded politicians.

        https://one.nhtsa.gov/people/outreach/traftech/1995/TT086.htm

        A grand total of 84 fatal crashes out of 485,104 from 1982 to involved a vehicle doing a right turn at an intersection where right turn on red was allowed. That includes both the green phase and the red phase, and only half of those involved pedestrians so the actual number of fatal crashes involving RTOR is somewhere between zero and 42. Probably closer to zero since a right turn on green is a more dangerous maneuver, since motorists have had a chance to speed up before crossing the parallel crosswalk as oposed to just stating out crossing the perpendicular crosswalk. All the people in cars that didn’t make a right on red will need to make a right on green.

        Here’s a study that showed that a right turn on red is no more hazardous than a right turn on green

        http://archives.sfmta.com/cms/rhomepd/documents/DPT_right_turn_on_red.pdf

        • Walker Angell
          Walker Angell July 10, 2019 at 5:09 pm #

          I somewhat agree with you though not entirely.

          First, the 84 number is per year and the 485k is for 10 years. The actual number was 852 out of 485k (not sure why they mixed measurements like that). Still small in the overall scheme. Though let’s be clear that we’re talking 852 human beings who were killed.

          As a percent of people walking and bicycling though it is much greater, I believe around 13% IIRC.

          When I did the Near Miss survey in 2008, RTOR was number three behind close pass and right hook (right turn on green when bicycle rider going straight has ROW). This is in line with my experience where cars not stopping for people in or entering a crossing is both dangerous and extremely unnerving even when someone is not killed.

          Finally, here again is a difference in the U.S. approach and EU approach. U.S. traffic engineers say it only increases fatalities by a little so it’s acceptable – a few people killed is OK. EU engineers say it increases fatalities (by any amount) and so not acceptable.

  6. karen Nelson July 9, 2019 at 10:06 am #

    Thanks, this is such a great overview and including local examples of Ramsey County is great.

    What is main reason we resist doing the best practice of separated bike lanes/paths a t sidewalk level on both sides of street and narrower car lanes?

    I have found many existing vehicular bicyclists would prefer in-street lanes to sidewalk level paths – which to me is unfortunate because biking will never expand much until we have bike infrastructure like the last example

    • Walker Angell
      Walker Angell July 9, 2019 at 11:03 am #

      Thanks Karen.

      The U.S. is a car centric environment, U.S. traffic engineers are car-centric and U.S. politicians are either car-centric or they simply listen to whatever the traffic engineers tell them. Anything related to walking or bicycling is not Transportation to them but merely Recreation.

      The lane width issues go back, I believe, to the 1970’s and a belief that wider vehicle lanes and clear zones next to them to allow for errors would be safer. The reality is that these only encouraged people to drive faster and most importantly to not pay close attention – because they’ve got gobs of room in case they make a mistake.

      Narrower lanes being safer is counter-intuitive and many people have difficulty with stuff that’s counter-intuitive. Countries like The Netherlands with legal prostitution have much lower rates of human trafficking and fewer problems with abuse of the women who work as prostitutes. Teens in The Netherlands are less than half as likely to smoke pot and about a third less likely to do other drugs. The stricter we make our drinking laws the greater problems we have, particularly with underage drinking.

  7. Daughter Number Three July 9, 2019 at 1:16 pm #

    While I love the concept of the last two examples (off-street bikeways with separate sidewalks on both sides of the roadway), I know part of the issue for Minnesota is how those bikeways get cleared of snow – is it the responsibility of the adjacent property owner, as the sidewalk is? Having the contiguous sidewalk path version makes for a 15′ wide path that can be cleared by equipment more easily than two separate paths, I would imagine.

    • Walker Angell
      Walker Angell July 9, 2019 at 1:26 pm #

      Great point.

      Shoreview is responsible for plowing and general maintenance of the protected bikeways along Ramsey County roads and generally do a good job. 2014 was an exception (https://streets.mn/2014/02/13/boneshaker-blues-and-public-works-departments/) and I actually chose to not ride some days due to the washboard ice in some places.

      FWIW, I am wholly against homeowners being responsible for clearing sidewalks. From what I’ve seen it doesn’t work and results in impassible places where homeowners miss or are late to get it done. Some also do a poor job resulting in icy/snowy spots that are dangerous. These problems are bad for anyone using the walkway but are particularly a problem for people with disabilities.

      • Brian July 9, 2019 at 4:05 pm #

        I used to live in Shoreview and a path in front of my house. It was fairly often they wouldn’t plow the path for a day or two after a storm. Long after they had already plowed the street once or even twice. They did have very powerful equipment to clear the trail.

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