I drove through it all yesterday and it was worse than previously. The reason appears to be work going on outside of the main tunnel construction close to the pavements in both directions. I think this was modifications or installations of electrical cables, so the traffic was being choked further. It is a bit dodgy on a bike, sure you can wend your way through but beware at weekends when Bangkok drivers are in the mix. They seem to be more aggressive and don't like to give way. Another thing to beware of would be people making their way home early or late evening, there is a chance they have been drinking, likely heavily, and patience becoming thin. I had 2 incidents (elsewhere not by the tunnel) over the weekend where I came across someone driving drunk as a skunk, no lights, on and off the road, and another where I believe a group of a few lads who had been at Bira or somewhere up Hwy 36 were coming home in their Nissan with a spoiler and noisy exhaust, looking for a bit of trouble and racing. Driving here is getting dodgier, and you are on your own out there.