Route Planning / Routing Choices

[irwinr]

Hello there,

I'm trying out ABRP for the first time and I'm noticing that, in Texas USA anyway, that it often takes a longer less efficient route than what might be otherwise possible. I was assuming that a tool like ABRP would choose routes based on distance and elevation gain/loss, but that doesn't appear to be the case.

Take this plan for example: https://abetterrouteplanner.com/?plan_uuid=45ba5eee-ecee-4d93-8be5-7c9dc0dff953

ABRP wants me to go 66 miles, hit Google's route would only take 54: https://goo.gl/maps/3PrECJSoxD2hq2ta8

I'm also a bit flummoxed by the estimated consumption of 4.69 miles/kWh... Under settings is lists the "reference" at 3.33 miles/kWh at 65 mph. These roads all have speed limits of 65, 70, or even 75 mph. So the average consumption should be *less* than 3.33 mi/kWh yet somehow it's estimating nearly 4.7?

-Jeremy

[Jason-ABRP]

Both of those issues are related to our routing engine (OSRM), and I'm working on resolving both soon, hopefully.  If you click on the route, you can see the speed and consumption we've planned for at that point along the trip, and wherever the speed limits are wrong, fix it in OSM (we provide a link at the bottom of the plan preview popup which will take you to the OSM edit page for that road).

Long-term, I'm also working on improving our initial speed estimates for roads, because they're very often wrong (especially in Texas!)

[irwinr]

Hi Jason,

I suspected that the speed limits might be wrong but then when I checked the speed limits they were actually correct. It's just the consumption numbers that are wrong. And ironically, the actual battery arrival percentages seem close to correct. So internally it must be doing the right math somewhere but the miles/kWh it's displaying are crazy high.

I'm more concerned with why it seems to favor longer routes with higher speed limits to begin with, rather than going shorter routes with slightly lower speed limits. I've had it tell me a few routes were un-workable until I hit "Avoid Highways" and then suddenly it works.

-Jeremy

 

[Jason-ABRP]

I've had the same thing on avoiding highways.  Something we should probably try internally when the routes fail on the first try.

It's all fairly complicated, but it boils down to the fact that we time-optimize the route planning, so it'll almost always choose driving faster and charging more frequently when possible.  It does lead to a few odd behaviors like what you're saying, where it initially picks the "faster" route that uses a highway, then later on in checking that route fails, but the non-highway route is rejected because it's too much slower than the highway route.

Thankfully such cases are fairly rare (in my experience), and we're aware of them and constantly improving the algorithm, so they should (hopefully) happen less as time goes on.

On the first note, though, I checked over the planned speeds on your route, and they're all under 55mph, which is much slower than you would expect to drive out west of Austin. (From experience).  I've been meaning to create a thread to solicit feedback on the US speeds, and this is the kick I need to go do it!

Link to that Thread

[Bill N]

8 hours ago, Jason (ABRP) said:

it boils down to the fact that we time-optimize the route planning

Slightly off-topic, but I wonder whether at some point you may be able to give users the option of choosing what they wish to optimize in favour of.

For example, some users may wish to optimize in favour of efficiency, or minimal total energy consumed, rather than time - both for the environmental benefits but also the financial benefits.

[logic]

Optimizing in favor of efficiency would make you drive at 40km/h / 25mph (see https://forum.abetterrouteplanner.com/uploads/monthly_2018_11/Analytical_Ioniq-Hyundai_Ioniq_range_metric.png.a4482bd2c5c86dc4fb85049bc63befd0.png from https://forum.abetterrouteplanner.com/blogs/entry/4-hyundai-ioniq-ev/) which is hardly realistic.

what you probably want is reducing the Max Speed to something you deem acceptable in both time and efficiency.

Edited June 24, 2019 by logic

[irwinr]

I don't really know the point of posting that since I think we all understand that the most efficient speed of an EV is around 25 MPH and I think you understand the point being made: taking a shorter more direct route saves so much energy that it's often hard to justify going to longer route to save just a few minutes of time. Whether it's about total efficiency or not: A shorter more direct route at slightly slower speeds uses considerably less energy than one that goes a lot further to favor faster interstate highways and often doesn't save much time. When I plug these routes into Google maps and compare the actual driving times I've seen ABRP takes routes that increase the distance by 20% or more for a time savings of less than 5 minutes. IE: A trip that could have been done in 50 miles will take 60 miles instead and both routes will have a driving time of just over an hour. Also: for those areas like the one I posted above west of Austin: There are no L3 chargers and in a first gen LEAF you're often relying on L2 charging to get home. Saving a little time driving at 75 costs far more time in added re-charge time.

However I think it's easiest to continue focusing on *time* efficiency... But when you do that factoring in L2 charging and HVAC use: I've done the math and the ideal speed when cranking the A/C and when relying on L2 chargers between stops is between 35-45 mph. Anything faster than that and your time savings from driving faster is more than eat up by the added time required to re-charge. I'm not advocating that ABRP tell you to limit your speeds per se, but if I'm driving in an area without L3 chargers and there's a shorter route on a 45 mph road or a 20% longer route on a 55 mph road, I'd prefer the 45 mph road because the time savings of driving faster won't even come close to offsetting the increased charging time.

So I think the point is it would be nice to tell ABRP that:

1.) It's OK to route to L2 chargers when L3 is not available.

2.) I should be able to indicate that I'm L2 charging at any particular stop I enter (Maybe it's a private home or business with an unlisted charging station)

And for routes that are relying on L2 rather than L3 charging the route planning might be better off focusing on distance rather than driving time.

And to re-iterate another point I made earlier: In the cases where it routes you onto an Interstate and then says something like "Max speed 45 mph": It would be great if it could opt to send you on a parallel access/feeder or business route if available because driving 45 mph on an interstate is not safe. There is usually a smaller road running parallel to the interstate where driving those speeds would be much safer.