The first thing you will need is to work out your access to the data - the web stuff will come later.
Since you are talking about "real time data" that you want to monitor, you will need to research OBD interfaces:
On-board diagnostics - Wikipedia[
^] and then probably start looking at mobile data:
A Practical Guide To Digital Data Collection - Wikibooks, open books for an open world[
^] and get some hardware sorted out.
That should probably feed into a online / cloud DB (but be careful - some of it may be covered by privacy legislation so you may need to securely store it / release to authorities on request).
And then you can start looking at the client interface end which is - let's face it - the trivial bit! :laugh: