The colours of markers on maps depend on the time since a traffic incident occurred. They help to give a quick indication of which incidents have happened recently, and therefore may have more impact on traffic flow.

As a guide:

Red Marker - Incident has happened in the last hour.
Orange Marker - Incident has happened in the last 2 hours.
Green Marker - Incident has happened more than 2 hours ago.

RSS or Really Simple Syndication, is a great way to keep up with dynamic web content. Instead of having to visit a web site or page to see if it has been updated, RSS feeds from sites allow you to receive updates in a "Feed Reader" and view all updates in one place.

Many Email readers have RSS functionality built into them, but there are many web based and desktop packages available.

Snarl uses RSS feeds so you can keep track of the traffic incidents that affect you without having to visit the site. It's just another way to use Snarl to make your drive easier.