Better Bike Lanes: Improving On What Got Us Here

Except for the boldest and most confident people, even experienced cyclists feel more comfortable – and more people are likely to use their bikes – when they are separated from fast moving or heavy traffic.  So it’s not surprising that the spread of standard bike lanes – a painted corridor sometimes against the curb but usually between parked cars and moving traffic – has been a powerful catalyst for the growth of cycling in recent years. Since safety comes from numbers, these facilities have significantly lowered the risk and improved the environment for bicycling.  Research shows that standard lanes increase the distance between cyclists and both moving and parked cars compared to unmarked streets -- nudging parked cars closer to the curb and bicycle riders further away.  But experience has also taught us that the next-to-the-driver-door location has significant flaws and that it’s possible to do better.  A lot of great design ideas have been developed.  However, outside the advocacy community, many people still haven’t heard about them.  Here is an introduction to a few of them.


Over the past decade bicycling has been transformed from a provocation by risk-taking street-warriors into the regular choice of many “ordinary” people.  Although still a small percentage of all trips, bicycling is now part of the urban scene.  In nearly every city and into the suburbs there are growing numbers of adult cyclists going to work, running errands, and visiting each other.  On popular commuter routes some intersections now have “bike jams” where people have to wait for a light cycle or two to get through.  The two-wheeled, muscle-powered flow now continues rain and shine, even through the winter.   Many of them sit more upright and go slower than their predecessors.  They more frequently wear helmets and are often wearing regular clothes rather than spandex.  Most dramatically different: growing numbers of them have kids or groceries in seats and trailers and “cargo boxes”.   From near total absence, bike facilities are now a standard part of transportation policies and design standards.

Fifteen years ago the much smaller bike world was dominated by macho  “vehicular cyclists” whose techniques for cycling in traffic are still useful but whose opposition to bike lanes and other bike facilities kept the community elite and small.  Today, bike advocacy is led by people who seek to encourage broader involvement and see cycling as a type of Active Transportation with a positive impact on other issues – neighborhood livability, car congestion, environmental pollution and climate change resilience, public health, equity, and economic development.  For some advocates, bikes are a necessary ingredient in the creation of sustainable cities, a key part of what makes cities desirable, prosperous, healthy, and happy – good places to live, work, and play.

As a result, the current decade has seen an amazing maturation of bike facility and road design as well.  From “share the road” signs, narrow shoulders, and shared lanes (sometimes with sharrows – bike symbols painted in the car lane) we moved to “standard bike lanes”, to today’s “physically protected” or “separated” bike lanes and intersections as well as traffic-calmed  slow zones, neighborways, bike highways or bike boulevards, and Greenways.  All this is pushed forward by a spreading demand for Complete Streets (which give walking, cycling, and transit facilities the same or higher priority than motorized traffic) and the adoption of Vision Zero policies (which seek to eliminate death and serious road injuries by, in part, redesigning streets).

It’s not surprising that the once-radical sharrow and standard bike lane are now being criticized as inadequate.  Sharrows do announce the legitimate presence of bicycles and help educate road users.  But sharrows are purely an attitudinal nudge rather than a traffic flow control and do little to reduce the stress on bicyclists or drivers stuck behind them.   Standard bike lanes are often too narrow – when located outside parked cars it is too easy for traffic-avoiding cyclists to veer closer to the parked-car side of the lane, putting themselves in a “door zone” where a driver’s unthinking exit can knock them into the way of passing vehicles: one of the leading causes of cyclist injuries and death.  (It would really help if new drivers could only pass their RMV road test if they used the “Dutch Reach” to open their door -- reaching over with their right hands which turns their head so it’s easier to see if another car or a bicyclist is approaching!)


There are effective ways to make better bike lanes and safer streets.  But the current chorus of attacks on next-to-parked-cars standard bike lanes as “killing fields” is dangerous in its own right.  We need to remember that these bike lanes have allowed many people to bike who were interested but afraid or concerned, and that it is possible to ride safely away from car doors in the vast majority of these lanes. Furthermore, there will continue to be roads too narrow or otherwise constrained to have anything else – and as past experience shows, having no bike lanes at all is an even worse option.  Most “ordinary” bicyclists – the “interested but cautious” majority – will simply not “take the lane” on a busy street.  They, and most of us, are not likely to be willing to plod forward at 10mph with a growing line of impatient rush-hour cars stuck behind.  When traffic is congested, and the noisy fumes are spewing, even the boldest among us have little pleasure in being part of the polluting mass.

The huge increase in today’s bicycling came from the addition of standard bike lanes.  Going forward with even better facilities will increase bicycling even more, contributing the “safety in numbers” dynamic of making roads safer for both cyclists and car drivers as they become more used to being with each other.  Whenever possible we need to demand more than standard bike lanes.  But we shouldn’t stop welcoming them where nothing else is possible.


On the other hand, there are easy ways to improve standard bike lanes, both against the curb and next-to-parking versions.  Visually separating a curb-side bike lane from moving traffic with “flex posts” or “bollards” will help keep drivers aware that they shouldn’t pass on the right.   (Studies in Canada show that these can be as much as 100 feet apart and, once established, can be easily unattached for winter snow plowing.)

On streets that have parallel parking on both sides, changing to “back-in angle parking” on one side retains roughly the same number of spots and allows drivers to see on-coming cars and bikes as they pull out.  It also allows the installation of a bike lane against the curb on the other side.  (These ideas are most easily applied on one-way streets:  Bow Street, in Somerville’s Union Square is a good example.)   Many streets with only enough width for parallel parking on one side alternate it from side to side on each block, or on different days.  Putting all the parking permanently on one side of the street allows a bike lane to be put next to the curb on the other side, away from the door zone.      

Where parallel parking has to be retained, instead of putting the bike lane on the driver’s side between the car and moving traffic, it is safer to move the cars away from the curb and put the bikes on the passenger side, between the car and the curb.  This takes advantage of the sad reality that most car trips are made solo, with no one in the vehicle except the driver.  If a passenger is present, it is still possible for that person to suddenly open a door in front of a moving cyclist which can cause injuries, but the rider will not be thrown into the street or under truck wheels.  And if there’s space to add a few feet of paint-stripped buffer space between the bike lane and the parked cars the odds of collision are further reduced.  Adding some vertical “flex posts” or planters in the buffer will make it less likely that parked cars will pull into the bike area.  This set up does require driver-side car occupants to exit into the traffic lane, but that’s what they already “normally” do on most streets.

The strongest protection comes from curbs.   Behind the curb a bike path can be at street or sidewalk level or somewhere in between.  This treatment often includes trees or bushes in storm-water retention pits, as well as devices such as swales to further capture and filter road run-off.  The strip of greenery can help separate the bike lane from the road (especially important if there still is parallel parking) or from the sidewalk in which case it can also contain benches and other socializing inducements.  Bus stop waiting areas can be included on the street side of the bikeway.  (Cambridge’s new Western Avenue is a good example of how this should be done.)  If the remaining road is inadequate for emergency vehicles the curb can be “mountable” (titled inwards) like the ones in many residential areas in western states. 


Just as dooring is the key danger along a road, turning cars is the threat at intersections.  Left-turning cars are a major cause of pedestrian deaths.  Right-turning cars hit cyclists.   A first step – important for car and pedestrian safety as much as for cyclists – is moving parked cars away from corners and “raising” the intersection or crosswalk.  At the cost of a couple parking spots it becomes significantly easier to see (and avoid) pedestrians and vehicles coming from the cross street.  It also allows easier turns by fire trucks. 

More open corners also create room for what is now being described as “protected intersections” that create separated pedestrian routes and bike lanes through the most dangerous part of the road.  A curb extension or island protects pedestrians and cyclists and forces turning cars enter the cross street at more of a right angle, making pedestrians and cyclists more visible.  Separate signals for each mode – cars, bikes, pedestrians – can also be used to add temporal in addition to physical protection for bicyclists (and pedestrians) where needed.

At a minimum, even if there isn’t money or space to create a protected intersection, bike lanes should be painted a highly visible green through the crossing to make it clear that they have a legitimate path.   If separate bike and pedestrian signals are not available, signage should allow bikes to go with the Walk signal – which should be timed to provide a 5 second head start (rather than the typical 3 seconds) giving pedestrians and bicyclists a chance to get across (or at least become visible) before cars can begin turning. Of course, this does not change bicyclists’ requirement to yield to crossing pedestrians.

Some European intersections now have bridges or tunnels for bicycles at particularly busy or complex intersections, notably at highway junctions.  It will be a long time before those become standard, especially here.  But they’re an intriguing example of creative thinking and effective safety-enhancing public investment.


The main strategy for improved safety is separation.  Our public right of way already has separate lanes for cars and for pedestrians, which we call sidewalks.   Now, people are demanding separate lanes for bicycles and perhaps for transit (buses and trolleys) as well.  But what about pushing separation even further – creating totally separate routes for non-motorized travel?

Several European countries are now creating Bicycle Highways – arterials for cyclists:  wide, two-way, totally dedicated paved paths from surrounding areas into major cities.  Planners see these as vital to continue boosting the percentage of commuters who bicycle rather than add their car to already overburdened roads, thereby providing a host of other benefits.

In this country, Frederick Law Olmstead pioneered the use of special paths for different users in his design for New York’s Central Park and Boston’s Emerald Necklace.   The national Rails-to-Trails movement translated the idea into a way to preserve the miles of abandoned railroad right-of-way corridors – many reaching deep into our cities and outward across entire regions – from getting lost in marginal expansion of abutters’ private property.

Our growing vulnerability to climate extremes has prompted the growth of Greenways – low traffic stress routes for non-motorized activity bordered by storm-water catch-basins, bushes, trees, and permeable-surface picnic or play areas.   If connected into seamless, region-wide network these facilities have enormous value for both recreation and mobility.  In eastern Massachusetts, the Emerald Network Initiative focuses on the urban core and the Land Line Coalition brings together the larger region. 


Instead of separation, what about togetherness?  What about eliminating all the lanes for everyone?  There is an entirely opposite strategy that is equally effective in the appropriate situations – of putting everything together using designs that force everyone to move in a way that prioritizes the safety of the most vulnerable.  Called “shared space,” these roadways violate traditional practice and are therefore controversial. The most common application of this design principle has been along the main streets of small business districts. Removing all curbs, signage, and signals forces pedestrians, bicycles, and motor vehicle drivers to all move slowly, paying attention to their surroundings and negotiating with each other.  In some locations, the absence of traffic light back-up actually lets vehicles get through the area in less time – slow but steady.  Many shared-space areas handle traffic smoothly and provide access to local users of the street.

There is, in addition, a much less radical version of the idea appropriate for low-traffic residential areas, sometimes called a “slow zone” or “neighborway”.  Without banning cars (although trucks require a special permit) the goal is to create a public space in which neighborhood families can play, picnic and party without the noise, pollution, or danger of fast moving cars pushing them off the pavement.   The speed limit is set very low – perhaps 5 mph – which is made self-enforcing by the installation of speed humps, raised crossings, curves, uneven pavement, or other techniques. The street also has in-road barriers at the ends (or in the middle) of the block to help keep movement slow.  Signs and pavement paintings are used to make the message explicit.  Resident and visitor parking is allowed, although limited.  Pushing the “play space” concept further, some Neighborways add play equipment.  Some are designed to maximize storm water retention.  Most have trees and other greenery.  The core idea is that the street space itself should be safe for children, with everyone else welcome but only on the condition that they act in ways that honor the code.

It is standard practice today to discourage through traffic in residential neighborhoods by using opposing one-way streets to reduce connectivity.  However, this also discourages bicycling by making it more difficult for cyclists, dependent on their muscles rather than fossil fuels, to take the most direct desire-line routes.  Neighborways, contra-flow lanes, and two-way bike paths are ways to create safe, pleasant, low-traffic routes for bikes without flooding a street with short-cutting cars.  This concept extends to larger-scale road design as well.  For example, many European cities have designed their streets so that a car cannot drive straight through the downtown. Instead, the driver must first go out to a ring road to navigate cross town. However, people on bikes can move directly between all the parts of the city quickly and easily. This has a two-fold effect. First, it moves regional traffic out of the city center making for a friendlier and more prosperous business district. Second, it encourages people living in the city center to not use their car for short trips. As Bostonians are already learning, it is almost always faster and easier to travel by bike (or walk or take transit) than to get through town by car.


Danish urban planner Jan Gehl says that the key to urban livability is to stop thinking that vehicular movement is the only or even the most important function of a street.  He strives to create “people priority streets” that are a public spaces available for a variety of purposes.

Of course, the needs of city and suburban town-center areas are different than those of exurban and rural locations.  But in regions of denser population the most powerful way to make bike lanes safer is to reduce the currently hard-to-avoid need to use a car to get around.   Ultimately, we need better trolley, subway, and bus systems.  But in the meantime – or at the same time – it is important to continue the amazingly rapid advance of bike safety design.


Thanks to Charlie Denison for insightful feedback on earlier drafts.


Related previous posts include:

> PEOPLE PRIORITY STREETS:  Neighborways, Slow Streets, And Safety Zones.

TRAFFIC CONGESTION: Why It’s Increasing And How To Reduce It

> MOVING BEYOND CAR LEVEL OF SERVICE (LOS): Measurable And Meaningful Criteria For Transportation Investments, Project Designs, And Development Mitigation



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