Forgiving bike lane separators

Posted on by 0 comment

An emergency vehicle using its siren is calling for general traffic to move aside to make free road space. If kerbs and street furniture are unforgiving, the risk of an emergency vehicle being locked in by general traffic increases. ‘Calming measures such as narrowing of usable road width and bumps should be occurring as little as possible’ (See notes at end of post). The photo below from North Melbourne shows bike lanes with painted separators, which would not prevent traffic from spreading with care.

Are painted bike lanes safe? “Cycle lanes provide a 30% safety improvement for pedestrians; this appears to be due to the buffer space provided” (NZTA pedestrian guide page 50). For cyclists, “overseas research indicates that the number of crashes decreased when on-roadway cycle lanes were installed; the reduction of cyclist crashes generally varied from [6.5%] 35% to 50%, … It was also found that narrower cycle lanes were three to four times less safe than wider cycle lanes.” (NZTA report 389 page 9) [you will need to read the full report to understand the context that generates the 6.5%]. The photo below, again from North Melbourne, shows plastic lump rumble strips on the outer edge to remind drivers to keep to their lane.

The next example is from Wuppertal Hardtufer. Here they have used low profile rubber separators. Being narrow, these have little effect on usable lane widths, and at 45mm high, the risk of pedal strike is low, allowing the full width of the bike path to be used, while vehicles can still move across it if needed. However, a point to note is that CROW states; “The application of rubber beams is only acceptable as an emergency measure for cycle-lanes with a minimum width of 2m” (p89).

One word of warning is that in Kuala Lumpur, the rubber separators needed to be removed within days of them being installed as they were unforgiving.

The above photo is typical of the separators used in the Raaalte Netherlands; these are “50mm high or less …  A verge or low edge enables the execution of emergency manoeuvres. A verge which can be ridden over gives overtaking cyclists enough space to occasionally deviate from the cycle-track”, as described in CROW, Forms of separation.

Notes below is my translation of the Swedish guide: Right speed in the city (Rätt fart i staden) from page29 of pdf

I have made some minor alterations to this to try to make it a bit clearer. Please check carefully in case I’ve actually altered any meanings unintentionally!

Emergency Traffic (Utryckningstrafik) page 27 [my emphasis]

For emergency services, it is the short time from when the alarm is received until the rescue force is in place and can begin work at the accident site, which is the most important requirement. As an example, one minute’s longer delay has an estimated social cost of over SEK 50,000 in a drowning accident, just under SEK 30,000 for fire in a building and about SEK 17,000 for a traffic accident.

The response time consists of turnout, driving and attack time. The turnout time is the time from the alarm being raised to when the first emergency vehicle is dispatched. The driving time is the time taken from when the emergency vehicle leaves the station to when it arrives at the scene of the accident. Attack time constitutes the time from when the emergency vehicle arrives at the scene of the accident and the operation is begun…..

The maximum response time from each fire station is decided by the municipality and is linked to the rescue service’s staffing, the location of the fire stations and the availability of emergency traffic routes. 

Maximum response time to an emergency target in a larger urban area is usually about 10 minutes, while in the countryside it can be 20-30 minutes and for remote places, longer than that.

Because the driving time is part of the response time and it applies to the total emergency route it is difficult to translate the requirement into a speed for an individual road section. The speed for emergency traffic instead relies on the average speed at which the rescue vehicles can travel along the emergency routes.

It is the individual accessibility for emergency services in terms of cross section, space and the possibility for other vehicles to move aside to leave a clear road that is most important. On streets that are part of the emergency traffic’s primary network, it is particularly important that speed-reducing measures such as side movements, narrowing and bumps occur as little as possible. Bumps can make the trip in an ambulance painful. Side movements or narrowing can make it difficult for rescue service vehicles to get around.

In the emergency network’s secondary network, which usually includes the local car traffic networks, lower speeds are acceptable provided that the total distance from the nearest exit from the primary network to the emergency target is not so long that the required response time cannot be achieved. On its last stretch up to the rescue target, for example, in neighbourhood streets and pedestrian streets with plantings and street furniture, a lower speed is acceptable provided the distance is short. Here, however, it is usually the physical design that limits emergency traffic accessibility.

The relationship between the distance from the fire station to emergency targets and the speed claim along the entire emergency route is illustrated in the diagram above [see link]. The speed claim relates to the average speed along the entire emergency route.

In the example above, the requirement is to reach 90 percent of the population within 10 minutes to achieve a good quality service. These requirements are formulated in different ways in the municipalities.

When the speed claim is examined, local decisions must be taken. What is the reality in any given place? Once the speed claim is calculated and the speed level needed to cope with the required intervention times is produced, the question must be asked: Is this reasonable? Can the road manager meet the speed claim or do other methods have to be tried to achieve the required response time? If the speed level becomes too high it will have negative effects in form of security and traffic safety.

When emergency vehicles use their sirens, calling for a clear road, this does not mean that they can choose speeds completely independent of other factors. It is not the speed limit that is limiting during deployment; there are other restrictions that exist along the emergency route. Examples of such restrictions are road geometry, speed limitation measures, traffic lanes, unprotected road users in close proximity to the emergency route, and road works. These factors should be checked in consultation with emergency services.


Category: News

Leave a Reply

Your email address will not be published.