Our large southwestern US metropolitan region has developed plans for expanding the current HOV system and add many miles to it. We are now at HOV 2+ and on some cognested corridors the speed differential between HOV lanes and nearest SOV lane is sometimes as high as 30-40 MPH. Here's our dilemma: our state statutes allow very large trucks (and tanler trucks) on our HOV lanes, as long as they meet the 2+ rule. This is a disaster waiting to happen during a peak period. What is the current practice on large truck restrictions on HOV lanes. Sadly, there is a reluctance to do anything about this until a fatal crash occurs. Why is it that FHWA has not instructed the states to restrict large trucks from HOV lanes - at least during peak periods?