Just for kicks, I used OSRM and added a large time penalty for taking left-hand turns. Here's the kind of route you get: http://imgur.com/VW63fq1 http://imgur

Just for kicks, I used OSRM and added a large time penalty for taking left-hand turns. Here's the kind of route you get: http://imgur.com/VW63fq1 http://imgur.com/VW63fq1 In reality, the metric probably needs to be a lot more complex than what I hacked together here. It's actually more like "don't turn left across traffic, left turns are ok onto one-way streets, etc", my metric was simply based on turn angle, and there are a bunch of scenarios where that falls down. The rule probably works well in travelling salesman-like scenarios - you want to optimize the route to deliver multiple packages. Having played with adjusting these kinds of metrics quite a bit, it's never as easy as you want :-(