Thursday, 24 March 2016

When upgrading main roadways, don't forget to not make it a barrier. How through roads should look and function in Edmonton

Many main roads for motor vehicles exist, and many need to be updated to meet Sustainable Safety's standards. But when you do that, don't forget to make the main road not a barrier.

Large roads can easily cut people off from one another. The US and many other places have learned this the hard way when they tried to built urban freeways. But they don't have to be barriers.

The Dutch found that there are many ways of maintaining people's ability to stay connected on either side of a main road. I propose an example road to see how this would work in action.

75 St, down to Argyll Rd, and after 101 Ave North, it becomes Wayne Gretzky Trail (if you aren't from Canada or the US or are unfamiliar with ice hockey, Wayne Gretzky was a star hockey player (he retired, he isn't dead), broke many records, played in Edmonton for a long time), is the route I want to upgrade to meet how Sustainable Safety would organize the roadway. Let's see what can be done to it.

The functionality of the road is the first thing to identify. It has some autoweg like characteristics, especially north of 101 Ave, but it also has parts where it functions like a distributor road. I classify it into two parts. North of 98 Ave, it would be an autoweg, as close to 100 km/h as possible speed limit, and regulated like one. South, down to Argyll Road (where it connects with the rest of my proposed grid of through roads for the city), it would be a 70 km/h urban through road. Both types require as close to free flow of traffic as possible, and a focus on flow not only on links, but also at junctions (flow at least as 75 St is concerned, the side road can be delayed with traffic lights or roundabouts or a right of way junction). Roundabouts and traffic lights are possible on a non motorway, but should be avoided.

Let's make it work on the street itself. The two directions need a divide where there isn't one already, especially at 70 km/h, sometimes more than that in the grade separated areas.

Next, because we want to make it easier to cross the road for vulnerable road users, and we can easily do that with underpasses, we can raise the road level itself up about 2 metres where we are going to place an underpass, so that you only need to descend down 1 metre (the foundation of the cycleway and sidewalk doesn't count). It's called a semi buried approach. This needs to not be a barrier to the communities. This blog post on the Aviewfromthecyclepath website shows how it's done: http://www.aviewfromthecyclepath.com/2014/08/why-tunnels-are-better-than-bridges-for.html.

The underpasses need to be spaced frequently, about every 500 metres apart. You are never further than about 250 metres away from one. Someone on the streets.mn blog did some calculations and (converting units into metric because that's what 95% of the world uses) to go from a stop to a speed of 18.5 km/h takes the same amount of energy as sustaining 18.5 km/h for 800 metres. This is partly where I got the indication that the underpasses need to be this far apart, or rather no further than this far apart. You would expend the same or less amount of energy stopping to wait for a traffic light. The other part of that the grid of cycle routes needs to be a very tight grid. Doing the math for the section between 101 Ave and Argyll Road, we would need between 7 and 8 underpasses. And remember, only some people would have the underpasses spaced at the distance limit to them, most people would be much closer.

On the north side of the 98 Ave, we will need a few updates to the cycle crossings we already have. The LRT crossing is almost perfect, it just needs widening and the construction of a separate sidewalk, plus some landscaping and good connections to cycle routes on either side of Wayne Gretzky Trail. Like how Assen not too long ago built a bridge for it's ring road over a canal, and a cycle path that paralleled that canal also was overpassed by the ring road, no change in elevation to the cycle path.

It is not as good to provide a crossing over the Drive at the Yellowhead. It isn't quite on the desire lines for pedestrians and cyclists, So let's create a crossing at Fort Road instead. We have the space to again raise the Drive 2 metres to create a semi buried approach underpass, and of course, return it to normal level at the interchange. It would work like just about any other underpass. Nothing really special. But what would be more interesting is the idea for a cycle bridge over the Yellowhead-Wayne Gretzky Drive interchange. It could be a location where we can build a turbo roundabout, and even if it wasn't, it would still be a much safer and more convenient crossing if we didn't have to interact with the motor traffic at all. Even at well designed signal intersections with this volume, there are still high rates of crashes. Motor vehicles have large and heavy metal shells. Cyclists and pedestrians don't. We can't build under the Yellowhead, at least not feasibly, so let's instead bridge it. We have enough room to provide a 3.5-4% gradient, which is very comfortable to take, and can be taken by all kinds of cyclists. Whether the interchange itself would become a turbo roundabout type, I don't know.
At 118 Ave, you can raise the Drive up a few metres, lets say 2 metres and make 118 Ave go a little bit down underneath, the roadway about 3 metres down, with the cyclists only needing to down 1 metre (trucks and other vehicles are restricted to 4.1 metres, so this will give some extra clearance. It would function probably like a diamond or possibly dumbbell interchange, given the space, I am guessing diamond with traffic lights. The Drive should continue to say up to cross 119 Ave with a motor vehicle and bicycle underpass. It is possible that an interchange with 118 Ave may prove unfeasible. If that is the case, then at least the cyclists and pedestrians should get an underpass.

Most of the little local businesses and collector roads and sometimes access roads can be closed off. We would replace the cycle and pedestrian routes with underpasses, and any non arterial road access that can be accessed via a different route should be closed. This makes it closer to the goal of monofunctionality, no local access, and it also makes cycle and walking routes shorter and more attractive.


Cyclists wanting to go parallel with the road would use the service roads on 75 St between 73 Ave and 101 Ave, that would be connected with short cycle paths where the service street ends. It would look and operate much like this street, except with a larger main road: https://bicycledutch.wordpress.com/2012/05/21/dutch-service-streets-and-cycling/. North of 101 Ave, there would be a separate cycling path on one side of the road in my vision, probably the west side as it would lead to an easier route on the north side of the River. Crossing either in the River Valley or at 101 Ave are options to get from northbound on the east side to northbound on the west side. Southbound is always on the west side. Next to the University of Concordia (not the place where the Concord was invented), there is a cycling path that roughly parallels Wayne Gretzky Drive and will lead almost up to the stadium, and makes for a good route.

Crossing the river either means a new bridge that is completely separate, my choice, especially if it was something like maybe 50 metres away, or on an expanded combined bridge, which would require extensive noise barrier systems. To get back up to the correct level, long loops to allow extra length to climb and thus a less steep incline should be used.

There are quire a number of other main arterial roads that cross 75 St/Wayne Gretzky Drive. Ideally they would be full interchanges. Some of them can't be due to costs, lack of space, etc. 98 Ave may or may not have an interchange. If it doesn't, then it should have a turbo roundabout. In either case, the road would be a very important one for motor traffic, a through road too. An underpass is required under a turbo roundabout, and even for an interchange, an underpass is still a good idea. 101 Ave should just have a simply flyover under or over Wayne Gretzky Drive. A simple underpass of 101 Ave would just be parallel with the Drive with access cycle paths leading to the cycle paths that would be built there.

Now that I've talked about the cycle routes, let's see what can be done to the road itself to make it closer to the goal of part 80-100 km/h autoweg and part 70 km/h urban through road.

The Dutch created a manual for designing roads that would be like this that I (and others) can access for free in English. It talks about autowegen and dual carriageways, what Europeans usually use when they are talking about roads that have a central median in the middle and more than one lane in each direction. This is quite helpful, so I'll draw from that manual, which you can read for yourself here: http://www.mnt.ee/failid/Safe_Road_Design_manual_FINAL.pdf.

An ideal autoweg has a divide between the two directions, a hard shoulder, a large clear zone, preferably 10 metres wide (otherwise a crash barrier is required), plus full grade separation. If interchanges are not possible, then roundabouts are a good option. Traffic lights and sign controlled junctions are to be avoided when possible. The latter two have proven to be among the most dangerous kinds of junctions you can build.

The ideal dual carriageway intended for 80 km/h traffic (I don't have numbers for 70 km/h traffic, but I'm under the impression that it would be safe at 70 as well, although speed limiting measures would be needed) would obviously have a divide between the two directions, with a crash barrier and 3.9 metre wide median, no local access, a non continuous edge line, at least 2 lanes per direction, limited access to local streets, ideally none, is closed to mopeds and bicycles, they have a service road or a cycle path, and no parking. Junctions to be grade separated, traffic light or roundabout controlled if possible.

Thus, the ideal dual carriageway distributor road should look like this: http://streetmix.net/CyclingEdmonton/317/divided-4-lane-70-kmh-road. This would also be quite close to how an autoweg would be built, although with 3.25 metre wide lanes and 10 metre wide clear zones on either side, 8 metres minimum without a safety barrier.

Not every place has enough room for that, so safety barriers are likely to be common along here. A noise barrier is needed anyway for much of the length of the road given how busy and fast, and noisy, it is. Adding lots of greenery too would help to shield the effects of this through road from the road. Here is an example of just how effective these noise barriers and visual screening can be: http://www.aviewfromthecyclepath.com/2015/05/a-car-crash-so-quiet-that-we-didnt-know.html.

Other interchanges also have to be built. At Argyll Road, it may be a standard interchange, like a diamond or dumbbell. Otherwise, a turbo roundabout could be built. There are many options for building roundabouts like these. Pretty much the only three remaining arterial roads would be 82 Ave, 90 Ave and Fort Road. Because 82 and 90 Avenues are so close together, and the environment they are in probably restricts interchanges, I think a turbo roundabout should be used. We could make each one into a three way roundabout, 90 Ave allows access to the East, 82 only offers access to the West. Fort Road could have a turbo roundabout or it could have traffic lights. It could be possible to remove the access and require traffic wanting to get on to use 118 Ave or other routes. It might not be possible, there are about 10K vehicles per day. Fort Road shouldn't be a through road and removing this access is one possible way to make it like that, but whether the other arterial roads will be able to handle the extra volume and the distances would still be acceptable, I don't know. Of course, bicycle underpasses are required in all of these cases.

On existing interchanges, the ramps often connect to traffic lights, only from eastbound on 101 Ave to northbound on Wayne Gretzky Drive are there no traffic lights. Many, and probably all, of them can be changed to dumbbell or dogbone roundabouts. They probably won't need a cycle and pedestrian grade separation due to the lower volumes and that you can use single lane roundabouts there. This makes it safer as well.

The road profile itself should change a little bit at other locations. Bus stops would need to be in dedicated bays  with tapers. The bus stops can be built into the noise barrier to make waiting for the bus more pleasant. Hard shoulders would be added in a few other locations on the areas classed as legally autowegen.

This design would eliminate practically every traffic light anywhere here. Maybe one at Fort Road, 90 Ave and 82 Ave, plus maybe Argyll Road and at the Yellowhead, but even if those couldn't be roundabouts or be closed, that would be a dramatic drop in the number of traffic lights. Between 9 and 14 sets of traffic lights could be removed, as well as a lot of the local accesses that constantly interfere with the traffic flow, and is very unsafe.

Electronic traffic control systems help to maximize the speed and safety, so that should be added too.

Why would I advocate for a road like this to be redesigned like this? Don't I want more cycling, walking and transit use? Yes, but this type of infrastructure can help enable that. By attracting more traffic to this road and making more capacity for it, it makes other roads have less volume, less need of four lanes or otherwise more than 1 lane per direction, more pleasant to ride next to, and with less requirement for traffic lights. Cars also by driving here, would bypass areas of the city where we really don't want motorized traffic light downtown. Their journeys may be longer, making it more likely that cycling and walking will be able to compete.

And I do drive, understand frustrations of drivers, and know how dangerous it can be. This road is also not sustainably safe, and by being a congestion prone area, there is more smog, as well as secondary accidents. By making the road safer and less congestion prone, but not making it harder for cyclists, pedestrians and buses to get around, it also helps to make the smog less likely to happen, as well as secondary accidents. And would you want your friend or yourself involved in a crash that could have been prevented by roadway design? I wouldn't.

By adding these noise barriers too, and cycle underpasses, people notice the road less, and have higher qualities of life without all of the noise and traffic right in front of you.

Overall this could be a very modern and capable road in East Edmonton, meeting Dutch design standards which have saved a lot of lives and prevented thousands of crashes and injuries over the years. Why not create a design that makes it so?

No comments:

Post a Comment

Thanks for commenting