I strongly believe a "good and efficient" public transport system - say a metro rail network would make a difference.

How can you assume that a major portion of the expatriates are laborers and hence don't affect the traffic and parking problems? At any one time if you compare the ratio of Expatriate driven cars on the road to Qatari driven cars , you will realize the expatriates outnumber Qatari driven vehicles quite easily.

The public transport you have in the country currently is nothing short of a joke. If the system were efficient, then most people would use it, irrespective of being an expatriate or a local. Having a vehicle at home does not mean it needs to be used all the time. If using the public transport meant shaving of an hour or more of commute from your day to day life, which would you use?