I found such a webapp. Its in German though. It can be found here: ADAC New Car Recommendations. The ADAC is the German club of car owners.
It works exactly like I would have liked it: I can select the elements that I need and place some preferences (like "Long Range Quality", "Transport capability") in a range from "I don't care" to "Super important".
Google Maps allows you to do this by setting road types you would rather avoid or by using "alternate route" methods.
To change a driving route, click and hold a spot on the route and drag it to a new spot on the map. If you're using Maps in Lite mode, you won't be able to drag to change routes.
Basically you let it plot your route then just drag around ...
I'm not quite sure about an app that allows you to specify your speed on different road types but from former experience using The Field Trip app (by Google) where it looks for sites of interest around you,allows you to mention certain road types(i'm not sure i just heard it from someone).
it's not much of an answer but i'll find out more and inform you when ...
Waze is a crowd sourced GPS application for Android. Users provide info on traffic, construction, speed traps, cameras and objects on the road. When you are nearing an item Waze informs you and you can confirm its existence or enter new warnings for others.
OsmAnd with the Trip Recording plugin
The Android app I use for recording trip data when driving is the excellent OsmAnd with its Trip Recording plugin.
The Trip Recording plugin allows you to record your trip and save it
as a GPX file. It uses your phone's GPS to track your movement. You
can view the route you've travelled, send it to OpenStreetMap ...
As commenters have stated, there are any number of apps that could do what you require to a greater or lesser degree, including Runkeeper itself.
After trying several, the one I have settled on is Cycledroid.
As the name suggests, it is aimed at cyclists. However, it exports the information that you require in GPX or KML format.
It doesn't try to match ...
If your police vehicles and speed cameras are clearly marked, in some countries they are not always, then you could use the OpenCV android implementation for something like this.
There are a number of resources and guides linked from this page as object detection, (not necessarily police vehicles), is a common problem in robotics. Beware of the simple ...
Here are some recommendations for Great Britain, which lead you step by step, through the various options mentioned in the question, to a selection of possibilities.
http://www.topgear.com/uk/car-chooser-launch (yay!! Top Gear !!)
http://www.carbuyer.co.uk/car-finder (good selection criteria)
https://www.carwow.co.uk/car-chooser (slighlty less selection ...