Narrow Street Usage

Map Editors Community Australia
1

Given that they are a fairly new road type, not many people have used the Narrow Street road type. They were introduced here on the forum and the discussion led to editors in the US deciding against using them at this stage. There was an update from Daliah here and confirmation that the road type was active here.

Active concerns are held over the viability of the penalty applied, house numbers not working and correct usage for the road type. I outlined an example of how the Narrow Street road type appears to work as intended in order to penalise routing through certain areas in the Local Traffic Only discussion. The outcome was that a route given for motorcycles that was as fast as another route was not provided for private vehicles, as seen below.

House Numbers
As there are concerns about house numbers not working, gating the entrances and exits to affected roads should hopefully allow us to apply the penalty while still allowing house numbers to work. Using the gating technique outline in the LTO discussion (for a single penalty) results in this at the 2m/10ft zoom level:

While I cannot guarantee that HNs will respond the same way as RPPs, RPPs do work within the gated area as seen below (1 Roosevelt Drive has successfully been moved from the north side of the park to the corner of Roosevelt Dr and Eisenhower St):

RPPs also work on segments that are set to Narrow Street, which means that gating might not be needed after all as gating would become troublesome in cases where there are multiple streets connected to the same narrow street (for example Fish Lane)

If there is in fact an issue with HNs, then RPPs might be a fix. The gating option may work for narrow streets with already existing HNs, but I haven’t tested that yet.

Penalty
At this stage there hasn’t been any clear indication on the exact penalty. A range of 5-10 minutes has been given. If a five minute penalty has been chosen, then a route will use the Narrow Street route over a Street route if the Street route is over five minutes slower. This could occur if peak hour traffic isn’t considered while setting the Narrow Street. While a Private Road segment could be used to provide a penalty, we have less of an understanding of the size of the penalty than we do with Narrow Street. Bear in mind that if a route using Narrow Streets is as fast as a route using Streets, an unexpected delay of over five minutes on the Street route could result in traffic being routed onto the Narrow Streets. The question is whether or not we wish for people to be sent onto Narrow Streets in situations where we might risk having two way traffic being sent off Streets onto single lane width Narrow Streets. Any potential congestion issues would depend on how fast the routing server can detect a slow in traffic approaching the Narrow Streets.

Usage
As the penalty seems to be less than the one for Private Roads, it gives us more flexibility when it comes to situations where we might want to limit through traffic under normal conditions while also allowing usage during unexpected circumstances. Motorcycles are the exception at this stage as the road type was intended for situations where the road is physically narrow and not as some form of Private Street Lite. The reduced penalty for normal vehicles is just an added benefit.

To determine the width of streets, True Segment Length allows us to see the length of a segment without having to save the segment. By starting a segment at one side of a road and finishing it at the other side of the road, we’re able to use the segment as a ruler. The following is the measurement, segment and Street View imagery for Hetherington Av:

As a comparison, here is Brunswick St:

If a definition of narrow is needed, then perhaps 5-5.5m wide (not including marked parking spaces) could be used?

2

Private Roads are for Private Installations and other roads that are not publicly routable and do not qualify as Parking Road. They shouldn’t appear in this discussion for the comparision of penalty weights, as the penalty for each serves a different purpose entirely. The only comparison that can be applied is the implementation of the penalty mechanism.

I believe 5.0 metres may be too large for the Narrow Street implemention, it will end up including entire new suburbs in this day and age of 3 square metre suburban blocks. It is more than suitable to permit two vehicles to pass safely without having to slow down and take effort to make room for each other. The road width outside my investment property at Upper Kedron measures at 4.7 metres and it is definitely big enough for traffic in both directions.

Fish Lane and Carol Lane by my measure are 3.0 metres wide and two-way. Very difficult for two cars to pass without one ducking into an actual driveway. These I would consider Narrow Street worthy.

Hetherington Avenue is 4.4 metres wide and two-way. There is room for two cars to pass without leaving the road surface itself, the parked cars make it difficult, but there are plenty of roads in Brisbane where parked cars make it difficult. Narrow Streets were added to fix a problem, we don’t really want them becoming overly commonplace throughout the suburbs (defeats the purpose of permitting the travel time to become the deciding factor).

Trying to find guidance on road widths, https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=12&ved=2ahUKEwjqsbTb0MzfAhXFgbwKHaZYB7QQFjALegQICBAC&url=https%3A%2F%2Fwww.tmr.qld.gov.au%2F-%2Fmedia%2Fbusind%2Ftechstdpubs%2FRoad-planning-and-design%2FRoad-planning-and-design-manual%2FCurrent-document%2FRPDM_Chapter4.pdf%3Fla%3Den&usg=AOvVaw2Ro3SviFq_iTok7OyfkUdx, shows a minimum of 4.4 metres for two-way through traffic on service roads and 3.4 metres for one way through traffic (Table 4.4, Page 4-30). I would not be making the cut-off for Narrow Street equal or greater than this as it would include far too many roads.

I propose that Narrow Street be used for anything two-way <4.4 metres wide and one-way <3.4 metres wide, or for road areas where the entire road length is a shared pedestrian area (Albert Street going into the mall for example https://www.waze.com/en-GB/editor?env=row&lon=153.02451&lat=-27.46908&zoom=9&segments=181052325).

3

LOL :smiley:

And narrow cul-de-sacs with nowhere to turn around without going into someone’s driveway.

4

Thanks for the link to the document. It’s good to go off a standard instead of having to make rough guesses like I did. In hindsight, the 5m suggestion probably isn’t necessary as the road only enters into the narrow category if there are cars parked on it:

As we cannot guarantee that there will always be cars parked along the road, it would be unwise to penalise routing along these roads. The routing server should be able to pick up any delays caused by queuing.

5

Hopefully this helps put car sizes into perspective. According to Canstar, the top selling cars of 2018 were the Toyota Hilux, Ford Ranger and Toyota Corolla. This website has the Toyota Hilux’s width as 1.85m, this website has the Ford Ranger’s width as 1.86m and this website has the Toyota Corolla’s width as 1.78m.

I’m not sure if it the measurements include mirrors, but it indicates that even popular utes are under 2m wide. The proposed 4.4m maximum width for Narrow Streets would allow 0.7 space between two Hiluxes passing each other. That’s less than the 1m safe distance for passing cyclists in Qld for roads with a speed of 60km/h or under. While it’s very close and there wouldn’t always be utes meeting each along these stretches of road, it does indicate that it is possible to fit two vehicles along those roads in clear road conditions.

6

I’m not sure we need a separate definition from that of the original.

I think the image provided in the post sets the scene well too:

Essentially if it’s a bidirectional road and there’s no possibility that two cars can drive down the road opposite ways and pass each other, I mark it as narrow. If it’s a one way road, it’s just a street with one way. There has been maybe 3-4 tiny lanes that have met this criteria from what I’ve seen so far.

TLDR:

If the cars can do this, it’s not a narrow street.

7

I agree with Brendan on this one.

The definition was clearly stated in the original thread when they released it. Despite not knowing what exactly these roads do, some editors rushed out and changed every road that was slightly narrower than a normal road to a Narrow Road, which was not the intended use (and also prompted the US to disable it).

Because these road types bear a penalty of 5-8 mins, I don’t recommend that we use this on two-way, one car width lanes. Other examples exist where it’s two way but one side has to give way for other traffic to go through first, like under-railway bridges of a certain kind. The nature of these roads is designed for two way traffic, with a stopping time. Would it not make sense to leave these roads as is, due to the segment travel timing affecting routing anyway?

The definition of these roads is “very slow to navigate through by car, but motorcycles should be fast”. Effectively this means if we don’t see slow segment travel times (for cars), we shouldn’t change it. In Australia this is very rarely applicable. In Europe, sure, some historic cities have super narrow roads. But I have yet to come across a situation where we’d need it (bar the weird LTO hack).

8

Hopefully this helps put car sizes into perspective. According to UK, the top selling cars of 2021 were the Toyota Hilux, Ford Ranger and Toyota Corolla. This website has the Toyota Hilux’s width as 1.85m, this website has the Ford Ranger’s width as 1.86m and this website has the Toyota Corolla’s width as 1.78m.

I’m not sure if it the measurements include mirrors, but it indicates that even popular utes are under 2m wide. The proposed 4.4m maximum width for Narrow Streets would allow 0.7 space between two Hiluxes passing each other. That’s less than the 1m safe distance for passing cyclists in Qld for roads with a speed of 60km/h or under. While it’s very close and there wouldn’t always be utes meeting each along these stretches of road, it does indicate that it is possible to fit two vehicles along those roads in clear road conditions.