Texas Transportation Institute (TTI) estimates that congestion is costing Americans more than $78 billion a year. Urban travelers are delayed in rush hour traffic nearly 40 hours a year. TTI has been publishing their annual urban mobility report since 1982. This year it is due out in April. Meanwhile, you can find data from previous year's report here.
Apart from mobility, there is a plethora of research publications from TTI on integrated public transit and even specific policy measures such as the effectiveness of HOV lanes in TX. Enjoy exploring the site on your own!