<s>[INST] Here are some proposals from concerned citizens to improve public transport in their city. 
 Proposal 1: Start a bike-sharing program 
 Proposal 2: Build an elevated highway system in the densest area of the city 
 Proposal 3: Limit vehicle owners to parking in only their own neighborhood 
 Proposal 4: Increase carpool lanes 

Which proposal is least desirable to transportation experts?[/INST]