The system, with buses and trucks obliged to go to Patong from the Phuket city side via Karon Hill or the coast road through Kamala, is expected to be in place ''within a couple of weeks.''
Authorities say they recognise that the one-way system for large vehicles will prevent crashes on Patong Hill but generate traffic problems around Chalong Circle and the Heroines Monument.
Drivers caught at Tungthong Checkpoint with alcohol or drugs in their system will face a 40,000 baht fine from now on, the meeting was told.
Vice Governor Jamleran Tipayapongtada chaired today's meeting at the Phuket Land Transport Offices in Phuket City. Governor Maitree Intrusud joined for a time but left before the meeting was over.
All truck and bus companies are to be informed about today's decision, which follows a fatal bus crash in Patong in which two people were killed during the 'Seven Days of Danger.' A number of other buses have crashed on the hill over the years, causing fatalities and serious injuries.
It was agreed that buses and trucks coming onto Phuket will be stopped at the Tachatchai checkpoint and told of the rule change once it is in place.
While authorities believe the rule will prevent crashes both on the hill approach - where some drivers have been unable to cope going up - and on the down slope to Patong, it was recognised that traffic at the Heroines Monument and at Chalong Circle will become worse as a result.
Two alternative suggestions were rejected. They were: stopping all large buses at the base of Patong Hill and transferring them to minivans and stopping buses from going over the hill between 6-9am and 4-7pm.
Motorcycle only lanes are to be delineated more clearly going over Patong Hill using yellow lines. In danger spots, the surface will be roughened to improve traction. Traffic flow will be improved with the roadway set to widen at the t-junction at the base of Patong Hill in Patong.
Efforts will be made to limit the age of large vehicles that traverse Patong Hill.
At an earlier meeting, Governor Maitree revealed there were 621 buses operating on Phuket with 1699 minivans. More than 50 percent are from other provinces.
Governor Maitree said he once counted 50 minivans passing on patong Hill in the space of just a minute. In October, he said, the underpass at Central Festival Phuket on the bypass road would be finished.