Thursday, 5 November 2015

Collector roads

A large chunk of the movement within a neighbourhood is done using collector roads. These in my area of Edmonton have a sidewalk on both sides, a grassed boulevard, parking on both sides and two lanes for general purpose traffic. They are the roads that tend to have stop sign controlled intersections with other collector roadways, bus routes and their stops, and schools and playgrounds are usually on these roads.

But how do we classify this type of roadway under Sustainable Safety's rule that roads must be as mono functional as much as possible, through roads, distributor roads and local access roads? Through roads don't make sense, but they tend to be where people live, but also connect local access roads and send the traffic to the arterials.

We have two options for dealing with this type of road. We can make it a distributor, have cycle lanes/cycle tracks, a 40 km/h speed limit and the right of way over side roads, or we could make it a local access road, cycling mixed with motor traffic, 30 km/h speed limits, no road at intersections with the right of way over any others and brick paving.

Lets see what the volume on a collector road fairly close to me is. Rutherford Road is the road I am picking. In the North of the neighbourhood, around 119 St, it is not uncommon for the volume to exceed 2000 vehicles per day. That would make me classify it as a distributor road. But wait, what about volume control? A fair bit of the traffic is shortcutting. Or traffic who should be going around the neighbourhood, using roads like 15 Ave to get to Johnny Bright school or 17 Ave to get to the Catholic school. This is very likely going to reduce the traffic by a lot. But it has the flaw that the volumes would be increased close to the school. It is likely that if you combine anti-shortcutting measures and making cycling and walking a safe thing to do, you are probably going to reduce the volumes by a high amount, maybe getting over 50% of people within 5 km to cycle or walk to school. I'd like to see it at 100%, maybe the rare parent dropping their late kid off (even though riding a bike would be faster under a good quality plan).

Though given the volume remaining, I will go with the distributor option.

This one would transform the street from a cross section like this: Collector road streetmix to one more like this: Collector road with sustainable safety. The existing model has 2 car parking lanes, 2 narrow sidewalks, a pair of boulevards, and 2 wide (but unmarked) lanes for motor traffic. The new model has one lane for car parking (it sounds bad, but just look at how many people could park their cars in the driveway or garage which in this area, all the residents have, businesses do not exist here, and visitors are uncommon), a pair or cycle lanes, a door zone buffer space for cyclists on the side with remaining car parking, a 5 metre bidirectional area in the middle of the road, widened sidewalks plus unchanged boulevards filled with trees and grass. The new situation also has a 40 km/h speed limit.

It looks weird seeing how narrow the 5 metre wide section in the middle is. And the fact that cars might need to enter the cycle lane. Lets see an actual example of this model: Overvecht Collector road. It is almost exactly the same as in the Edmonton model. It lacks boulevards but has a widened sidewalk. Parking is in the grey brick bays, marked with white bricks. It is very similar to my example. Lets see what bus stops would look like. Cross section: Collector road at bus stop. It has a bypass, required when the speeds exceed 30 km/h, and no car parking on either side. The cycle lane remains wide enough to pass within the lane.

Intersections would be very different then the ones we know and hate today. They are much more friendly to those walking and cycling, and make sure that people understand that when you come out of a distributor road to the 30 km/h zone, you are in a very different street type. Picture here: Gateway treatment. You have a steep speed table, where the sidewalk continues as if nothing happened, and a sign saying 30 km/h zone. In this particular example, there are cycle lanes on the distributor. Roundabouts are also possible, even at this size. Here is my inspiration: roundabout with cycle track around it. The roundabout central island is not mandatory at small roundabouts. A video made by the FHWA (Federal Highway Administration US) shows the concept of mini roundabouts. It is missing cycle tracks (to be clear, if possible, use the 6 metre long gap between cycle track and car ring, it is not always possible though) shows what can be done if you do not have the needed space for the regular central island. Link here: Mini roundabout. Note that if you mix bicycles and cars, then you need to have low volumes and speeds of 30 km/h. Mixing won't work unless that is present.

If you still do not have the space needed for a roundabout, then option two is a right of way intersection. One or more of the approaches has a yield sign (or stop sign, but it is better if we don't think about those), and the remaining road does not stop. With two distributors, it will look a bit like this:

So that is the basic picture for collector roads. They have 40 km/h speed limits, low to medium volumes of traffic, cycle lanes or cycle paths, cycle paths for most uses where the volume is over 3000 vpd or near schools and parks, or where cycle lanes would make people fear, and not used as the main road for traffic between neighbourhoods. 

Update 10:00 AM Friday Nov 6 

I forgot to mention that by putting parking on one side of the road, you can switch it around maybe every 80-150 metres, creating an effective chicane. 

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