MapQuest has added current traffic conditions for more than 100 metropolitan areas; more details and a list of the cities covered are available here.

Digital Earth Blog has an early review: “A quick glance seems to show that they have more cities than Google, but not by a wide margin. … Assuming their data is accurate, the clear winner appears to be MapQuest. Google has much of the highway in gray (”no data”), while MapQuest is showing data for everything. In addition, MapQuest has the clickable icons so you know exactly what the problem is.” But the lack of a mobile version is a dealbreaker: “For me, however, 95% of my Google Maps traffic usage is from my cell phone while I’m on the road. … As far as I know, MapQuest has nothing to compare to that.”