Phetchaburi itself is blissfully free of traffic snarls, except on the main North-South highway that bisects the Province but by-passes the town.
There are no meter taxis. There are tuk-tuks, motorcycle taxis, and for a slow cruise around the market area, plenty of traditional two-seat pedal-power tricycle taxis. Whatever your means of transportation, it would be a good idea to have your destination written down in Thai for the driver.
For longer journeys around the Province there are local buses trucks with benches available from the market area, but you need to ask the drivers for their destinations you will quickly be directed to the correct bus.
Most of the important temples except Khao Wang are within walking distance of the market area.