Is IQ Routing More Hype than Reality?

[tangentproject]

There is a route I take from my house that requires a U-turn when I first get onto the street. Then it is a straight drive for some KMs, make 1 simple left turn and park the car.

If I plot this route using Shortest Route (which doesn't use IQ routing) I will get the exact route that I take with an estimated time of 18 minutes. If I plot the same route using Fastest Route with IQ routing it sends me on an extra 1.3 km route to circle back to the point where I normally make the u-turn, then it takes me on the exact same route with an estimated time of 15 minutes.

My question is simply how is it possible to take essentially the exact same route but adding an extra km or so but be 3 minutes quicker?

Another blip is that the actual time it takes with IQ routing's extra distance and turns is very close to what it estimated. However, the time it takes from the shortest route's calculation is much shorter than estimated. So I am thinking: IQ Routing may not be calculating the best routes but only gives the most accurate time estimate compared to not using IQ routing.

In other words IQ routing only looks better when comparing route times against non-IQ routes but the shortest route calculation may give better and faster routes but offer a less correct estimate of time.

Any observations by anyone who has had their device for a while and tried different routing options?

 

[mvl]

I've found IQ routing to be very good (near perfect, and better routes than I would drive), with the exception of u-turns and rush hour traffic.

IQ routing adds a 5 minute delay per uturn, for safety purposes (either with or without IQroutes). What you're seeing is that tomtom prefers a roundabout route because it has no uturns, and takes less than the uturn route time plus 5 minutes.

There is no preference to remove the uturn delay globally, but you can fix it one-at-a-time via mapshare. See here:

https://www.tomtomforums.com/showthread.php?t=15619

 

[tangentproject]

That is an interesting point regarding the 5 minute time "penalty" for making a U-turn. I didn't know that. It helps explain the time differentials between routing methods but is IQ routing actually better, or just different, perhaps even taking longer than non-IQ routing?

 

[mvl]

The difference between IQ routing and non-IQ routing is the road speeds that are used to compute a route.

IQ routing uses historical speed info submitted by tomtom users via the "submit anonymous data" feature in tomtom home. If you run route demos, you can see how IQ routing slows down for stop signs, traffic lights, congestion backups, etc.

Non-IQ routing uses a fixed speed based on how wide a road is. It is a reasonable approximation but causes lots of misestimations and un-optimal routing, especially in cities.

I've found IQ routing to be very good, and well worth the upgrade to a GO model.

 

[mvl]

Just noticed this podcast from teleatlas (from last November) that describes IQroutes. Nothing not mentioned before in the forums, but a good synopsis.

http://c4.libsyn.com/media/1819/Epi...15&nva=20081118163815&t=05a01597f9bcccfb68420