Yes, traffic is an issue on Sint Maarten. Especially in the Simpson Bay area, cars move only with a snail's pace during some hours of the day. The frequent openings of the draw bridge, allowing yachts into the lagoon, are causing serious traffic problems during morning and afternoon hours.
Below is the opening schedule for the Dutch side bridges:
Airport Road Bridge:
08:30 AM outbound boats
09:30 AM incoming boats
10:30 AM out
11:30 AM in
3:00 PM in
4:00 PM out
5:00 PM in
Causeway Bridge:
08:00 AM
10:00 AM
3:30 PM
These are the official times, but there are also irregular openings for mega yachts, who pay extra for the privilege of interrupting the flow of traffic. The bridge stays open for up to 15 minutes, in some cases longer if the yachts' skippers take it too easy and leave large gaps between the yachts entering the channel.
After 4.00pm, don't try to get from the Cupecoy/Maho region into Simpson Bay or even Philipsburg. Most likely, you will be stuck on Airport Road for a while. After 6.00pm, traffic clears up.
To get to Marigot from Simpson Bay, the Maho area and Cupecoy, use the pleasant road through the Lowlands. It might be a mile or two longer, but you'll arrive half an hour earlier. Do your Philipsburg shopping in the morning, and you will avoid the traffic build up during the afternoon hours.
