Portland, Oregon is one of several U.S. cities with a progressive bicycling culture. A couple of innovations the city has implemented are "bike boxes" and "sharrows".

Bike boxes are road markings that designate exactly where cyclists and motorists should place their vehicles when stopped at an intersection with a red light. The main idea is to prevent the notorious "right hook" as a cause of collisions. The jury is still out in terms of effectiveness, but bike boxes are receiving mostly positive reviews so far. (On wikipedia these are called Advanced Stop Lines and around here they're called "green boxes".)

Sharrows are shared lane road markings on roads/lanes shared by cyclists and motor vehicles. In Portland, they are found on city designated bike routes without bike lanes. The idea being that it's a visual cue to cyclists and motorists that the lane is to be shared.

Question: What are other infrastructure modifications a community can make to enhance bicycling safety?

  • Converted to community wiki, there will be several answers. Also, sharrows work remarkably well (or they did in Boston when I was there.) Commented Oct 20, 2010 at 19:43
  • @wdypdx22 - The two examples you cite could probably be answers all on their own. Commented Oct 20, 2010 at 23:01
  • True... I was in a bit of a dilemma when posing the question on whether to use them as examples or to potentially give answers to my own question. With only ~3 months in the stackexchange universe I'm still working on optimization. ;~)
    – user313
    Commented Oct 20, 2010 at 23:17
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    @wdypdx22 - No reason they can't be both; perhaps expand them a bit as answers? Commented Oct 21, 2010 at 6:28
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    Here's Yehuda Moon's take on sharrows. Commented Feb 10, 2011 at 17:48

11 Answers 11


Bike Loops (sensors for traffic lights)

One thing we have in the SF bay area are markings on the road where a bike can stand to trigger a green light. In intersections where the lights are governed by sensors, bikes can't usually trigger those, and end up having to either run the light, push the pedestrian crossing button, or wait for a car to show up. With these markings, cyclists can know where a more sensitive sensor is places that is more likely to trigger the light.

alt text

  • 3
    That is an awesome idea - At least two sensors on my primary route to work must be triggered by a car. Fortunately there is usually significant traffic in the area.
    – Gary.Ray
    Commented Oct 20, 2010 at 19:19
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    Nice. It also shows drivers that cyclists have a right to be there, similar to bike boxes at intersections. Commented Oct 20, 2010 at 19:50
  • I put in a title, but do these things have an actual name? Commented Oct 20, 2010 at 23:01
  • I think they're called bike loops :)
    – zigdon
    Commented Oct 21, 2010 at 6:24
  • Duct-tape a big rare-earth-metal magnet to your bottom bracket if you get annoyed by this car-sized induction loops ignoring you. Commented Oct 21, 2010 at 7:42

Bicycle traffic lights are used in some cities at intersections with bike lanes or bike paths.

On the streets, they can be synchronized with turn signals so that cars are prohibited from turning while bikes can ride through an intersection, and vice-versa.

alt text

And at their best, they're placed at cyclist's eye-level (with redundant red, like rail signals, even!) and combined with separate cycle crosswalks.

Vienna bike signal across the Ring, facing the Staatsoper

  • There are several places on my commute where I really wish I had these. Commented Oct 21, 2010 at 12:22
  • ...same here, excellent idea.
    – user652
    Commented Feb 19, 2011 at 2:29

Portland has also developed one of the greatest solutions ever: Bicycle Boulevards.

On bicycle boulevards, stop signs are turned to keep cyclists moving, and traffic lights and curb extensions help cyclists cross busy streets. Traffic calming slows cars down, and drivers are discouraged from using them for cut-throughs.

It's remarkable how well they work. Speed bumps, curb bumpouts, relatively low speed limits, and intersections where cars can only turn but bicycles can continue straight reveal much of the promise of healthy car-bike-pedestrian interaction. Portland of course has the advantage of a nicely-parallel street grid, where bicycle boulevards can be situated one block off major arterials. Seattle, in contrast, has few locations suitable for this due to the hilly topography and location of the major thoroughfares.

  • 1
    Vancouver has many cycle routes one block off the main routes. But they have the normal back street traffic pattern of a stop every alternate block - they also have the problem that every few blocks you have a major cross street and because you aren't at the main street junction you generally don't have lights.
    – mgb
    Commented Oct 26, 2010 at 22:40
  • I mostly love Portland's bike boulevards, but the force-turn devices (the mini-traffic circles to slow cars down) seem to do more harm than good. While they do slow down cars, it's terrifying to bike through an intersection with the turns when a car is trying to pass (there's not enough room to do it safely), and it's scary as a driver when coming up behind a bike near one of the circles. Frankly, I think we could do without the circles.
    – nhinkle
    Commented Dec 1, 2010 at 4:31

Bike lockers and garages, e.g. at commuter rail interchanges: "safety" as in "your bike not being stolen".


One of the best safety improvements I've seen in recent years is the conversion of wide inner-city roads to narrow roads with a separated bicycle path on both sides. Streetview example. Of course, outside cycling nations you'd need a very bicycle friendly city council to realise stuff like this.

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    There's a set of something similar along my commute, but they're flush with the sidewalk instead of being recessed. Because of that, pedestrians just use them as extra sidewalk, which quite frustrating sometimes as I need to be constantly dodging pedestrians. Commented Oct 21, 2010 at 12:25

Everything that leads to more bicycles on the streets is a safety innovation: more cycles means that car drivers become aware of their presence and thus drive more carefully. Anyway car speed decreases and reduces the risk of accidents.

Bike sharing facilities, such as Vélib' in Paris, are one of these safety innovations.

Among others are: contraflow cycle tracks and bus lanes open to cycles.


One-way streets that are open to cyclists in both directions. These are becoming more and more popular in Germany, where they are commonly called "unechte Einbahnstraßen" ("mock one-way streets").

In cities, one-way streets often exist no because the road is really too narrow, but simply to limit the number of cars passing through. At the same time, such one-way streets are a real hindrance to cyclists, who prefer smaller streets. Mock one-way streets nicely solve this problem.

One-way cycle exemption ("except") in Vienna's old city

I worked in a bicycle advocacy group (ADFC) which has been promoting these for years. Often, local authorities, especially police, have grave security concerns - but experience and research have shown that they are quite safe.

sign for Unechte Einbahnstraße


20 sign

20 mph speed limits

A review of 20 mph zones in London found that there was an average reduction in casualties of 42%, compared with an 8% reduction in surrounding areas. Although injuries amongst cyclists reduced at a lower rate than other users (only 17%), this does not take account of the fact that cycling levels increased much more than for other modes.

So lower speed limits result in fewer injuries to cyclists, even with increased numbers of cyclists.


Congestion charging: a very effective way of reducing the number of cars on the road, and increasing the average skill of the drivers that remain (since an increasing proportion of the remaining drivers are professional drivers).


Cycle hire (a.k.a. bike sharing) systems.

Cycle hire station, Broadwick St. Soho, London UK

By democratizing and popularizing riding, and making it a taken-for-granted part of the transport infrastructure. More bikes also mean more bike-awareness, and more widespread participation and interest in biking, which drives support for all other safety improvements.


Bike paths with sensor-operated traffic lights at road crossings. In Christchurch (NZ) there's a path next to the railway line where the sensors are timed so that a cyclist at 20-30kph gets a green light at the crossing (most of the time, in rush hour there's a longer car cycle). It makes riding that route quite joyous. Almost like the Netherlands :)

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