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Sometimes I feel like my navigation system assumes I'll drive 140km/h on the German highway, which is not a terrible estimate for the average German, but it still seems a little high as a general assumption.

Since I'm planning a trip from Düsseldorf to Leipzig (all across the country), this made me curious: what does the navigation system actually use as a base value? If it's too high, I should account for that in my ETA (since I need to check into the hotel before a certain time).

  • "but it still seems a little high as a general assumption" - maybe you can generalize this impression across all route types; e.g. Google Maps almost always assumes a higher speed (and thus a shorter travel time) than what can actually be achieved in my experience, and that is true for both highway routes and slow routes through cities and villages. – O. R. Mapper Dec 18 '17 at 17:04
  • The speed used in the estimates is probably too high. While there are many highways that theoretically do not have speed limits, in practice many have speed limits of 80 or 60 due to "construction works" (which in practice means one or two lanes are closed; it's shocking how little road crews you see in Germany) – MSalters Dec 19 '17 at 10:23
  • @MSalters Any data on the actual, average speed on highways would be welcome! I too noticed lots of roadworks are there for many months or even a few years, while in the Netherlands they are usually gone within a month (unless it's a big tunnel project or something). – Luc Dec 19 '17 at 12:36
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    @Luc: A good example is the Rheinbrucke near Leverkusen, which carries the important A1 highway. It's been under construction since 2012 and will be until 2025. In comparison, the Dutch A1 is also under active renovation, and has been closed for about 10 weekends (!) – MSalters Dec 19 '17 at 15:53
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Looking in open source applications is one approach. OsmAnd is an application for Android that I've used in the past and has given fairly accurate ETAs. This was quite fruitless though, as the only thing I found was 40km/h applied when maxspeed is set to none (the standard way of tagging this, as an absent value might mean "unknown" or "not mapped yet").

Testing OsmAnd by routing over a piece of highway that has maxspeed=none set for almost 40 kilometers, I get around 133km/h. An odd value, but the best estimate that I could make given multiple measurements (different parts of the same stretch). The application reports the estimated ascend and descend, but it's hit and miss: if I see a relatively steep incline at point X and I route 3 kilometers before and after point X, it will suddenly not see the incline anymore. It also doesn't seem to take this into account at all.

OSRM, another routing engine for OpenStreetMap has 140km/h coded in. Testing this service via the interface at openstreetmap.org however, I find that it reports speeds of around 115km/h ±2. At this point I've given up on deep-dives into source code.

Mapzen, also through the openstreetmap.org interface, gives me 105km/h ±1.

GraphHopper, also through the openstreetmap.org interface, gives me 120km/h ±0.003. Finally one that is consistent and makes sense.

YourNavigation, which seems to use Gosmore as the routing engine (operating on OpenStreetMap data), gives me 108km/h ±1. I get the feeling it's one of the older, less-maintained services and it appears to be an outlier in terms of speed.

Google Maps simply does not compute. At 04:30 in the morning, it cannot make up its mind about whether I'll take 8 or 12 minutes to do 15.8km. Hence the speed estimates are between 80km/h and 118km/h at 04:30 in the morning. I'd advise caution when using Google Maps to estimate your ETA and rather use another, more sane service that does not rely 100% on algorithms and 0% on sense.

Bing Maps seems to calculate with 130-135km/h, using its "without traffic" estimate. Currently (15:00 in Germany) it reports "light traffic" on this stretch, which brings the speed down to 115km/h.

Waze also takes traffic into account and has no option to turn it off. The results are quite varied/unreliable, though not as bad as Google's: between 105.6km/h and 125.2km/h at 04:30AM (across 7 tests: all subsets of the same stretch of highway as I tested the previous services with). Again, use common sense, because at 04:30 you'll not suddenly get stuck in 105km/h traffic for 19km, especially when an overlapping stretch of 18km drives 121km/h. (For the Americans, 105-121km/h is is 65-75mph.)

Conclusion

It depends. Some services estimate around 110-115km/h, and others assume you'll reach the advisory speed in Germany of 130km/h.

In the past I've had good results with OsmAnd which is on the 115km/h side, so I suppose there is something to say for accounting some 10% of variance in traffic, curves, etc.

For services that try to take current traffic into account, make sure to apply common sense.

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    Welcome to Travel. Great answer! Make sure you stick around. – JoErNanO Dec 18 '17 at 15:08
  • You should also add a Waze estimate - it's the best app by far for driving navigation. – JonathanReez Dec 18 '17 at 15:28
  • @JonathanReez Added Waze. Good one, I kind of ran out of ideas :) – Luc Dec 18 '17 at 15:51
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    Another consideration - don't use the "driving estimate" feature to set the time to 04:30. It's unreliable and doesn't work well. Instead, use the real time driving estimates for leaving right now. I then get an average of 125 km/h on Google Maps for driving on the A20 right now, which is more than reasonable. – JonathanReez Dec 18 '17 at 15:58
  • My TomTom seems to calculate around 110km/h on 130km/h roads, so not that much off from the others either. – Belle-Sophie Dec 18 '17 at 20:55
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Forget navigation, from my driving experience you can assume a straight 100 km/h to get a good estimate.

The thing is what I call speed paradox: The slow parts of the trip are dominating the average speed, so fast driving does not reduce the travel time as much as you think.

Let's say we drive 120 km (US citizens can half all values and replace them with miles). A 60 km section has road construction, so this part has a maximum speed of 80 km/h, otherwise you have unlimited speed and you are driving the remaining 60 km with 160 km/h.

If you estimate it, you would think something like one part is 80 km/h and the other part is 160 km/h, so I will drive on average the middle speed, 120 km/h.

But the real average speed is: 45 min for the 60 km with 80 km/h, 22,5 min for the 60 km with 160 km/h. So the average speed is 120 km / 67,5 min ~ 107 km/h.

If you try to drive faster to increase the average speed, the result is:

180 km/h = 20 min => Av: 110 km/h
200 km/h = 18 min => Av: 114 km/h
240 km/h = 15 min => Av: 120 km/h

Even if you drive ridiculously fast you wont't be able to increase the average speed much.

Add

  • parts where the speed is shortly reduced: road work, dangerous spot etc.
  • you need to take a few minute breaks for fuel and relaxing
  • you need to overtake slower trucks from time to time

and your true average speed will drop under the perceived average speed to a good estimate of 100 km/h.

  • While this might be interesting and helpful for OP's plans, I don't see how this answers the question asked. – martin.koeberl Dec 19 '17 at 1:10
  • @martin.koeberl It answers OP’s second question ‘If the speed assumed is too high, should I account for that in my estimate?’ – Jan Dec 19 '17 at 5:06
  • You may want to note that 100 km/h is the typical motorway estimate while Germans (or at least my family and some friends) estimate 80 km/h on country roads. – Jan Dec 19 '17 at 5:07
  • @Jan I'm not sure where you are taking that quote from. What you're quoting doesn't appear in the original post. Maybe OP should've or wanted to ask(ed) something different but it's not up to the person answering to decide that (and from their own answer it doesn't seem to be this way). – martin.koeberl Dec 19 '17 at 5:14
  • @martin.koeberl I quoted from memory. Here is the copy and past (last sentence): ‘If it's too high, I should account for that in my ETA (since I need to check into the hotel before a certain time).’ – Jan Dec 19 '17 at 5:17
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What is "the navigation system" for you? You need to specifiy the navigation system, because different navigation systems might have different default values.

I am a German and using 3 navigation systems in my car my experience is, that they assume 130 km/h for limitless highways. This is according to the "Richtgeschwindigkeit" a suggestion from the Federal Ministry of Transport and Digital Infrastructure which recommends to drive 130km/h on limitless highways (please not, this is only a suggestion from the Ministry, not the maximum allowed speed)

  • Which three navigation systems do you use? The question is quite generic: anything that helps with car route navigation and provides an ETA is in scope to me. – Luc Dec 19 '17 at 12:34
  • I use systems from the brands "Becker" and "TomTom". If you have a system available, usually you can change the default speed in the settings – Gnusper Dec 19 '17 at 12:48

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