Usually nowadays, the Causeway taffic condition bothways is usually not so heavy and quite smooth.
There are days when there is a huge jam on SG's side, I notice the jam was usually caused by the thorough check on cars at the customs side and sometimes a second check by anti-narcotics officers before the exit causing a bottleneck.
I guess those were days when they got winds of some smuggling activities attempts about to happen.
I find the drive back to JB to be much easier after the S'pore immigration. The bridge is almost always free flowing - obviously because the bottleneck is from the S'pore side. Likewise, because the bottleneck is from the S'pore side, the bridge is chocked in the morning. For a country that prides itself for being efficient, I'm thinking they can and have to do better than this. Sure, security is important but there should be a way to distinguish low-risk daily commuters from the casual visitors.