I was messing around with the traffic function in Google Maps to look at Alabama's four largest cities and their traffic patterns on their freeway system. None of this is by any means as comprehensive as a traffic study; just some observations from patterns that Google Maps shows at different times of the day. These may not be entirely accurate either, or it may be biased towards more recent data, which could skew results. With that said, overall, it seems like Birmingham/Hoover and Mobile have worse traffic than Huntsville/Decatur and Montgomery. Some other observations:
- I would rank Mobile as actually having the worst traffic of all four due to the bottleneck of the Wallace Tunnel on I-10. Remove that, and Mobile's traffic situation would seem to improve. Due to tourist traffic (I assume) I-10 between Tillman's Corner and Daphne has some congested spots during the weekends. Of course, the Wallace Tunnel bottleneck is worse during the weekends because of this.
- Montgomery seems to mostly not have any bottlenecks on its interstate system with the exception of I-65 northbound out of Montgomery towards Prattville on Friday afternoons. Why are we spending all of this money on a bypass of Montgomery where that money could be better used elsewhere?
- Birmingham's largest problem is I-65 from I-20/59 south to US 31 in Alabaster. There seems to also be congestion along I-59 near Trussville from the Clay/Chalkville to I-459. Congestion on I-65 northbound and southbound at I-459 can cause traffic to back up along the ramps in the I-65/459 interchange.
- In Birmingham, there seems to be a backup along Red Mountain Expressway (or Elton B. Stephens Expressway, whatever is your cup of tea) (US 31/280) going north to the ramp to I-20/59 west/southbound. The section between that interchange and I-65 seems to get congested as well.
- In Birmingham, the I-20 westbound to I-20/59 southbound movement gets congested due to the sharpness of the ramp.
- Huntsville/Decatur shows a bottleneck along I-65 at the Tennessee River bridge, but I don't think this is entirely accurate because a lot of the recent data included the lane closures along the bridge for maintenance work.
- Most of Huntsville's problems are at the interchanges themselves (I-565/AL 255/Madison Pike and I-565/Memorial Pkwy/US 72, and yes I consider that one large interchange complex). Memorial Pkwy is quite congested at rush hour between US 72 and Airport Road, but this isn't reflected as much with Google's logged data.