Athens Real-Time Traffic Map
A map plotting the density of traffic on the Greek capital's main arterial roads.
http://transport.ntua.gr/map/index.html

ITS Online
Table of real-time traffic maps on the Net. Most are in the US, although there are a few from abroad listed too.
http://www.itsonline.com/rttable.html

New Jersey TIDE Center
Links to traffic maps, traffic cameras, transit conditions, and road construction reports for major cities across America and Canada.
http://www.njtide.org/links/systems.html

Rand McNally
Road construction maps for North America.
http://www.randmcnally.com/rmc/tools/roadConstructionSearch.jsp

Speed Camera Maps
An interactive map of the UK highlighting speed cameras.
http://www.speedcameramap.co.uk/

Traffic England
Detailed real-time traffic reports for the whole of England. You can also access sister sites for Scotland and Wales via homepage.
http://www.trafficengland.co.uk/TCC/
http://www.trafficscotland.org/
http://www.traffic-wales.com/

Traffic Eye
Get the lowdown on UK traffic conditions before you set off.
http://www.trafficeye.co.uk/

Traffic.com
Traffic reports from a number of major US cities using interactive maps.
http://www.traffic.com/

Travel Advisory News Network
You can access traffic maps for several US cities at this site.
http://traffic.tann.net/

Travel Forecast.com
Offers state-by-state traffic and road construction maps.
http://www.travelforecast.com/htdocs/roadconditions.asp

Vauxhall Trafficnet
Simply move your mouse over the map and select the area which you want to get up-to-date traffic information for. Alternatively, you can click and drag the map window to navigate.
http://buypower.vauxhall.co.uk/trafficnet/