It really needs a bypass.... but slip roads will help the general flow on the A27, but it doesn't seem very future-proof.
I know cars are evil currently, so shouldn't be encouraged, but in the not too distant future most cars will be either hybrid, electric or hydrogen fuel cell vehicles...
The traffic coming north from LA to Crossbush gets stuck for 2 reasons....
1. The cars cutting in at the lights cause the junction to be blocked even after the lights have changes, allowing only a few cars through from the south.
2. Some cars fly up the left, turn left and then turn round in...
Getting through / round Arundel can take a VERY long time, with the tailbacks at Crossbush heading West (can be 15 - 20 minutes, and sometimes worse), at the roundabout just past the railway station (all the way down the hill sometimes) and on the old bypass in the lead up to the roundabout over...