Enhancements will be made to the driverless shuttle rides in Punggol before revenue rides begin, the Land Transport Authority (LTA) said on Wednesday (July 29).Service operator Grab will be trialling an on-demand service that lets users book a direct shuttle between any existing pick-up and drop-off points.Trial riders will be able to access Grab's pilot service in the next few months before it is gradually opened to the public in the fourth qua…