sound off….on roundabouts

In my introduction of a couple of days ago, I indicated that I was a fan of traffic circles. That was in fact a poor choice of words, as what I am really in favour of are yield at entry roundabouts vice traffic circles. What’s the difference I hear you exclaim, they all make me dizzy and probably they are unsafe and do they really work as advertised? If they are so good, why aren’t they in use in Kingston? Why did Kingston eliminate the traffic circle at Princes and Bath?

First lets address the differences, then dispel any fears you might have regarding their safety, and demonstrate some additional benefits. Finally I will propose one or two locations to try them out and challenge you to sound off – do you like them? Hate them? Why?.

cross posted at Kingstonist.

Traffic circles (or rotariesas they are sometimes known) are quite often multi lane one way circular traffic patterns with multiple entries and exits – they are often quite large and intimidating. Due to their large circumference, traffic within the circle can move at high speeds which can intimidate drivers. Roundabouts by comparison are small radius traffic control installations, with the following common features – (1) yield at entry – that is traffic within the circle has the right of way, (2) due to their small circumference, traffic entering and moving through the roundabout moves at lower speeds thus reducing both the incidence and severity of accidents and (3) are often used to replace signalised junctions at medium volume intersections.

modernroundaboutsafety1Roundabouts offer marked safety improvements in at least two significant areas – vehicle to vehicle collisions and vehicle to pedestrian collisions. The number and severity of vehicle collisions has been demonstrated to decrease, particularly as roundabouts eliminate both head on and left turn accidents. This is not to say that there are no accidents at all, but rather that roundabouts reduce the potential relative speed of vehicle to vehicle accidents resulting considerably less insurance adjusted claims. Secondly, vehicle to pedestrian accidents are much reduced due to the elimination of left turns (a surprising source of many vehicle to pedestrian accidents).

Finally, what added benefits to roundabouts offer? Significantly, traffic continues to flow rather than to stop altogether – numerous studies have demonstrated that when traffic continues to flow even at a reduced speed in certain areas, the total trip distance is reduced. Roundabouts contribute to a decrease in vehicle generated pollution as both idle times while stopped are eliminated, and the higher consumption generated by acceleration following a green traffic signal is reduced or eliminated altogether.

Where to start? I suggest two trial intersections, one in the east end and one in the west end. Replace the traffic signals at signalised intersections Craftsman (the back gate to CFB Kingston) and Highway 15 and in the west end at Midland and the Walmart entrance with roundabouts.


2 thoughts on “sound off….on roundabouts

  1. Junior,
    As part of my job as a consulting transportation engineer I am a roundabout planner designer, living in Kingston. Good info is around and your post was a good start. Many long time residents of Kingston remember the old Kingston Circle and instantly think that is what a roundabout is. That just isn’t what roundabouts are.

    Your suggestions for “trial” locations are okay but there are better candidate intersections around the City (and adjacent area). As mentioned Highway 15 and Highway 2 would be good location for one. They can handle high volumes of traffic if properly analyzed and designed.

    Two roundabouts are in the planning and design stages. The first is a provincial project in Picton on Highway 33 at County Road 1. It is supposed to be built this year. The second is on Highway 2 at County Road 4 between Napanee and Kingston. The status of that one is currently unknown but it may be built this year.

    Two more roundabouts will be opening in Kemptville this year (in addition to the one that is already there).

    Stephen Sargeant

  2. Oddly, I wasn’t thinking of the T-Junction at Hwy 2 and Hwy 15, but rather the back gate a little further north along Hwy 15. Since most of the afternoon traffic heads north on 15 flowing out of the base and very little turns left onto 15 and likewise in the morning there is very little traffic going north on 15, I figured a roundabout would have been better than the lights installed about two years ago.

    I have become quite a fan of roundabouts as I have become familar with them in my travels to Germany. Some might argue that there are on occasion too many of them, but on the whole I quite like them.
    cheers, Junior

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