Traffic has been getting worse here in C.Rai, though not due to rain, we haven't had a drop in 10 weeks, (and there won't be any rain for the next 6 months).
Traffic in general, particularly on larger roads, could move a lot better if the following improvements were enacted:
A. People not running red lights. Happens often - at least 10,000 times per hour in just one small city of Chiang Rai, probably 20 times that often in Bangkok. When vehicles run red lights, it's not only dangerous (duh!) but it slows cross traffic, which has to wait to get started. Plus the last cars could be left in the intersection, further bolloxing up traffic flows.