# Does a metric for road quality exist and are there maps showing it?

While planning a road trip spanning several countries I am having some doubts regarding estimates provided by Google Maps due to potentially poor roads. For example, this tour spans 13191 km and supposedly takes only 182 hours which gives an average of 72km/h. I've done some parts of this before where one can do 100 km/h or more in Ecuador and Peru but roads in Bolivia rarely could be driven past 50 km/h. I've not gone beyond Potosi before but since these roads pass through the Amazon jungle, I do not expect such velocity as I have taken other roads cutting through the Amazon before and could not exceed 30 km/h comfortably in most parts.

Does Google Maps know the actual speed that people drive on those roads or does it simply use the official speed limit? If the latter, how can we get a better estimate of reasonable speed to travel along a given road? I realize the actual speed driven depends on the vehicle and weather so I'm not looking for exact numbers just better estimates.

• I've heard Waze is extremely popular in Peru, even taxi/uber drivers use it Commented Jun 8, 2016 at 20:56
• Many paper maps have color codes to represent just that. Don't if you'd fine one for Ecuador, though. Commented Jun 8, 2016 at 21:03
• With regards to Google, they use a variety of factors to calculate road speed. Which of those factors are available for those roads in that part of the world, I can't say. If you're really motivated, Google exposes some of that data in this API, but I believe it requires a paid license. Commented Jun 9, 2016 at 0:14
• Commented Jun 9, 2016 at 10:18
• Peru is no problem, neither is Ecuador, I've driven both these countries end-to-end several times and the quality of most major roads are excellent. Bolivia is worrying me and most is the part of Brazil Google is indicating to do this trip.
– Itai
Commented Jun 9, 2016 at 12:33

Google's official Map Maker lists the following information in their guideline for map contributors:

Average (avg.) speed

Speed limits show how fast someone can drive legally. When getting directions in Google Maps, speed limits help calculate travel time.

Default speeds: Roads in every country have a default speed limit depending on the road priority, surface type, and the country’s speed guidelines. If you're not sure about the speed value, leave it as default. Some segments might have different speed limits and should be changed to ensure best routing. Verify the speed limit by looking at posted signs in Street View (where available).

Therefore Google doesn't calculate the average road speed by looking at actual travel speeds, or at least it doesn't do so directly. If you wish to verify their assumptions you could try viewing a given road on Street View. Ecuador, Peru and Bolivia all have partial Street View coverage, so it should be possible to view at least part of the route before going:

• Google has the ability to do this though. On any Android phone you can review your history on a map (if you have it enabled), surely they could work this stuff out? Commented Jun 9, 2016 at 9:55
• @Berwyn they definitely do this for their traffic feature, but I'm not sure if it's enabled otherwise. Commented Jun 9, 2016 at 9:57
• @Berwyn It could, if they wanted to spend money and time doing it. I doubt that Google will start mapping road quality data from Bolivia... they will probably start with highly populated areas where they have a lot of users and only finally end up in places like Bolivia. Commented Jun 9, 2016 at 11:42
• @Bakuriu I wasn't meaning that they'd map road quality itself, just average speed on that road with and without traffic. Commented Jun 9, 2016 at 11:46
• I recommend to be accurate with Google Street View visual quality estimations. If you miss 10-20% of extra bad road part while browsing then you can double real time after that :) And very often 3-5 year old photos can differ a lot with reality, specially after winter seasons. Commented Jun 25, 2017 at 14:42