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Re: Bus controlled traffic lights

Posted: 25 Mar 2019, 12:09pm
by Pete Owens
For a give way or roundabout it is even more important to get into the correct lane; drivers at the give way line are overwhelmingly paying attention to the road they are trying to join so are likely to fail to notice a bus or cyclist approaching from behind. In this example you can see that the gap in the bus lane has had to be made longer:
https://www.google.com/maps/@53.3993508,-2.6459956,3a,75y,233.13h,74.82t/data=!3m6!1e1!3m4!1s40SuGR6CzcLvrF_FX3IyPQ!2e0!7i13312!8i6656.
Yes, that does mean slightly less priority, but only because it is an extraordinarily bad idea to overtake a stream of traffic that is turning across your path.

Ideally at a junction such as this there would be a compact roundabout with single-lane approaches and exists on all arms. General traffic would need to merge into the bus lane on the approach. The way to ensure priority would be to install a set of lights to control the merge. These could would be set to give a long red stage to the general traffic in advance of a bus approaching, so when the bus reaches the end of the bus lane the queue will have cleared.

Re: Bus controlled traffic lights

Posted: 25 Mar 2019, 1:21pm
by Vorpal
In the USA, when bus or bike lanes become turn lanes (usually right turn lanes, as they drive on the right), drivers entering the turn lane still have to give way to bikes or buses already in the lane.

They are labelled with a sign, something like
Right turn lane begins
Yield to bikes & buses

Some of them have symbols, like a merging arrow, with one coming form the left, and the other coming from the diamond used for bike & bus lanes, there.

Re: Bus controlled traffic lights

Posted: 25 Mar 2019, 1:22pm
by Bmblbzzz
There's what might be called a hybrid system here:
https://goo.gl/maps/BY8Nzd3Zi3w
The general traffic lanes lead up to signals on to the roundabout, but the bus lane bypasses the signals and ends in a give way line. Possibly there's a system to hold the lights for that road on red when a bus is in the give way? I don't know. It does allow the buses to stop off at a conveniently sited stop right by the roundabout, rather than a hundred metres back, so hopefully increasing the attractiveness of the buses. I don't think any of the buses from that direction turn right there.

Another curiosity is that the streetview seems to have been filmed from the pavement, presumably using some sort of backpack-mounted camera.

Re: Bus controlled traffic lights

Posted: 25 Mar 2019, 1:43pm
by MikeF
Pete Owens wrote:Ideally at a junction such as this there would be a compact roundabout with single-lane approaches and exists on all arms. General traffic would need to merge into the bus lane on the approach. The way to ensure priority would be to install a set of lights to control the merge. These could would be set to give a long red stage to the general traffic in advance of a bus approaching, so when the bus reaches the end of the bus lane the queue will have cleared.
As in my example above and repeated here.
Bus controlled lights Other motor traffic is held to allow the bus to pass. In this case buses go straight ahead and through a bus gate. I think the bus sensor is immediately after the last bus stop, which is some way back.

Re: Bus controlled traffic lights

Posted: 25 Mar 2019, 8:37pm
by brynpoeth
Pete Owens wrote:
StephenW wrote:
What about bus lanes in the middle of the road, rather than at the kerbside?


Would make getting on and off the bus a bit exciting.

There are some in Hamburg* for example, the stops are protected by barriers and there are lights so PoFs can cross
Many trams run in the middle of the road, when they stop vehicles have to wait, undertaking is not allowed
* used to be served by three-segment bendy buses :?

Re: Bus controlled traffic lights

Posted: 26 Mar 2019, 8:51am
by Bmblbzzz
As noted earlier, either 100% of passengers cross half the road or 50% of passengers cross all the road. However, central stops do require extra building and in UK there is no tram priority law.

Re: Bus controlled traffic lights

Posted: 26 Mar 2019, 9:28am
by Pete Owens
Stepping off a bus into a live traffic lane is rather different prospect to crossing half a road.

Re: Bus controlled traffic lights

Posted: 26 Mar 2019, 10:09am
by Bmblbzzz
Central stops, or more accurately island stops. Not necessarily a good idea though, for one thing it means the bus lane isn't really usable by cyclists.

Re: Bus controlled traffic lights

Posted: 26 Mar 2019, 12:00pm
by Vorpal
Oslo has island stops, mostly for trams, but also for buses in a few places.

There is normally a pedestrian crossing from the island to the footway.

I just use the lane that goes around the stop. A couple of busy streets also have a cycle lane. Some have tracks in the middle for trams (not other traffic), a general travel lane, and a cycle lane, like this https://www.google.no/maps/@59.9217884, ... 312!8i6656

Re: Bus controlled traffic lights

Posted: 26 Mar 2019, 1:11pm
by Bmblbzzz
That cycle lane looks nice and wide.

Re: Bus controlled traffic lights

Posted: 26 Mar 2019, 1:24pm
by Vorpal
Bmblbzzz wrote:That cycle lane looks nice and wide.

It's almost wide enough to avoid the doors opening from parked cars & still stay in the lane!

Re: Bus controlled traffic lights

Posted: 26 Mar 2019, 1:51pm
by Pete Owens

Well I suppose if you start off with an 8-lane carriageway with a modest volume of traffic you can allocate 2 lanes for trams + 2 lanes for islands + 2 lanes for general traffic + 2 lanes for parking bays - and if you make all of those a bit narrower than normal traffic lanes you can squeeze in a door-zone cycle lane.

But do we really want to allocate quite so much of our cities real estate to transport infrastucture?

Re: Bus controlled traffic lights

Posted: 26 Mar 2019, 2:29pm
by Vorpal
Pete Owens wrote:But do we really want to allocate quite so much of our cities real estate to transport infrastucture?

No, and building new housing & infrastructure, Oslo doesn't do that, either. The width of that street hasn't changed much in 200 years. It used to be the main route out of Oslo to the south.

Re: Bus controlled traffic lights

Posted: 26 Mar 2019, 3:23pm
by mjr
Pete Owens wrote:

Well I suppose if you start off with an 8-lane carriageway with a modest volume of traffic you can allocate 2 lanes for trams + 2 lanes for islands + 2 lanes for general traffic + 2 lanes for parking bays - and if you make all of those a bit narrower than normal traffic lanes you can squeeze in a door-zone cycle lane.

But do we really want to allocate quite so much of our cities real estate to transport infrastucture?

It seems so here, as parts of the main road into our medium-sized town is now 9 carriageway lanes across (westbound 1 left, 3 ahead, 1 right; eastbound 2 left, 2 right) while everyone walking and cycling is directed into one 3m sidepath (but plenty ignore it and walk/cycle "wild" across the carriageway and along the verge, generating angry comment from motorists in local press) and buses get stuck in the jams of general traffic.

IMO it's high time to reallocate the roads and build for what we want to encourage, instead of repeatedly failing to build out of congestion. Some should become busway and some should become cycleway.

Re: Bus controlled traffic lights

Posted: 26 Mar 2019, 3:26pm
by Bmblbzzz
Yes. And some should become buildings, greenery, etc.