Here's a good way to ease congestion - charge people more money for using the roads, and then provide a train:

"More Salik gates may be installed on Dubai roads in a bid to get more people to use the Dubai Metro, Mattar Al Tayer, Chairman of the Board and Executive Director of Transport at the Roads Transport Authority (RTA) said at a media briefing after the inauguration of the Metro, Wednesday night."
http://khaleejtimes.com/dubaimetro/inside_metro.asp?xfile=/data/metro/20...
Since they charge people money to drive on the road in Dubai, it's only a matter of time before they do the same in Doha.