Other than a simple user interface which can act like ‘SkyNet’ to invent robots to hunt down sarah conner…
How about a WAP portal, for the site, especially the Road watch section. I mean, most people are home and dry before they notice the possible issues on the road. And posting about it too late to properly help out the rest of the guys.
Updates can be sent to a unique email address, via mobile phone (via MMS and many phones can use SMTP).
A simple page detailing the road/area, type of problem, and some footnotes, is all that is needed and it would be relativly inexpensive for users on mobile.
I think it will allow people without regular internet access to join in, as mobile phones are used by more people, word of mouth can spread it amongst couriers/commuters, therefore greater information input. (even car users can update police hotspots and road closed problems.
It could also be updated by a manual update using the traffic watch on other traffic websites/reports. Maybe an RSS feed could assit with updates?