The projected house building target needs to be reduced and traffic calming measures on local roads increased.

Transport Assessment validity of the data used: 

The CATM model has been validated and calibrated using 2014 counts. Using 2014 data means that significant changes such as the opening of Chichester Free School immediately next to the A27 Whyke roundabout, with over 1000 pupils and over 140 staff may not have been considered. 

This data is now 9 years old.
  
The Transport Assessment states that "it should be noted that even prior to adding in the Local Plan development, all the junctions on the A27 Chichester bypass are over capacity in one or both modelled peak hours. With the exception of Portfield Roundabout, the junctions are also shown to be over or very near capacity in the base year model (2014) before any additional background or Local Plan traffic is added, highlighting the fact that it is not just the Local Plan or committed Chichester development which leads to this situation."  

Whilst only 28% of traffic growth can be linked to committed and proposed Local Plan developments, if the mitigation measures only apply to Fishbourne and Bognor roundabouts, then the problem with over capacity still remains. 

Therefore, the plan is not effectively mitigating the impact of the addition growth and is adding further demands on capacity which is already exceeded, therefore the housing number should be challenged further.