On Sat, Mar 12, 2016 at 7:12 AM, Arun Ganesh <arun.plane...@gmail.com> wrote:
> this means that all turn:lanes, change:lanes, access:lanes, >> forward:lanes, backward:lanes, etc. should count ALL lanes > > > Turn lanes meant for a turn in a particular direction at the junction. I'm > not sure if the concept of a turn lane extends to a cycle? > At least in most of the US, yes. Yes it does. Heck, bicycle specific turning facilities are becoming more common, too, to the point of being routine in cities with busy bicycle infrastructure (or planning well ahead for it). Even if not the case, it can be helpful for routers to know which lane might allow a vehicle but be the designated lane for a specific mode (truck and bicycle designated lanes, for example, will tend to perform slower than general lanes; likewise, bus and HOV lanes will tend to perform faster). Lane guidance need not necessarily be about the next turn exclusively, having a lane suggestion in open traffic (for example in Osmand, before the next turn arrow turns yellow) can be handy. For example, say you're driving Interstate 30 lengthwise through the DFW metroplex. That city has freeways that are typically four roadways, sometimes six (and more wouldn't surprise me). Which gets you through most efficiently? The carpool express road? The expressway? Or the local road? Or a couple real world examples from experience: You're on US 75 HOV South, and you need to get to the Dallas Intercontinental Hotel in Farmer's Branch. Which exit do you take to get back on US 75 South, to have ample time to make it across 5 lanes of traffic to take the best crossover to the local lanes with access to surface streets? As I found out the hard way, the answer is "The first HOV exit" since the second one won't come until a few feet after the ramp you need to take miles down the road, and I ended up on I 685 HOV almost until Dallas International Airport and had to backtrack a dozen miles. Another one, and one I frequently used a CB to guide truckers through traffic on (since they tend to hold a more consistent speed and are good at preventing people from cutting you off; just get behind one going your way, talk 'em through getting out of Portland, and suddenly driving the Banfield's like riding the MAX with a stereo without having to run down Burnside)... say you've just left I 5 North to get on I 84 East in Portland, Oregon. You're trying to get to the truck stops in Troutdale, preferably with enough time left over to eat and get a shower before you legally have to sleep before you get on the road again the next morning. There's three lanes, and you still have 18 miles to go, 9 before the two busiest interchanges in the state. Traffic is manageable but quickly squeezing together and slowing down fast. Most truckers would go with the middle or probably the right lane out of instinct, but this will get you stuck in exit only lanes unannounced until the last minute, forcing lane changes in unyielding traffic. The correct answer would be "use the leftmost lane and don't leave it", that lane leaves downtown Portland, and by the time you get to Troutdale, it's the exit only lane for your truck stop: You only have a direct shot if you stay left on the I-5 to I 84 ramp and stick to that lane all the way. Knowing this saves you 30-45 minutes travel time (and time is money). > The turn lane data should provide enough information to a car driver on > which lane to take for a turn. Its obviously important to know the presence > of a cycle lane in between the car turn lanes for proper guidance, and the > main questions is if the `turn:lane` key is suitable for capturing this > data. > I'm not sure it needs to be car specific. The lane usage needs may vary by mode, it's important that supported modes be able to take this information into account. From experience, the farther away you get from a midsize sedan or station wagon in terms of size, weight, acceleration, braking and top speed, the more likely you're going to need to know which lane you need to be in, and possibly how early you're either able or legally allowed to be in it. And bicycle left turn lanes, particularly in Portland, are often the rightmost possible lane, swinging across all other traffic when that lane's released, and much shorter than the general lanes. Washington DC has at least one bicycle facility where through traffic uses the right lane, and all turns, left or right, uses the left lane (the bicycle lanes are the centermost lanes, instead of the outside lanes). People don't know this stuff if they're not a roadgeek, and even if they are, they may not necessarily have the exact pattern memorized for the distances required to be efficient at knowing the pattern.
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