This year's Royal Lancashire Agricultural Show is to be held at Myerscough from July 18-20 with more than 60,000 people expected to attend the event.
Police say there will be congestion around the show area and are advising drivers who are not attending the event to be patient or use alternative routes where possible.
Sgt Nigel Ralphson from the Northern Division's Road Policing Unit said: "We are expecting a large amount of visitors to the show to have an enjoyable day out.
"This is the first time the show has been held here and working with the Lancashire County Council and the Royal Lancashire Agricultural Society we have taken every step to ensure the minimum disruption to both local and show traffic occurs. However it is inevitable that there will be some delays on the routes around the showground.
"I anticipate that Broughton Island and the Broughton Crossroads will be the main areas of congestion for traffic in the Preston area, while the village of St Michael's on Wyre may experience some tailbacks on the A586.
"Both these areas should be avoided if at all possible between 8am-noon and 4-7pm. We will do our utmost to keep traffic flowing but I ask that everyone is patient and shows consideration for other road users."
With a number of other high profile events also taking place on the same weekend including the British Open at Royal Birkdale and the Tall Ships Race weekend in Liverpool, David Grunwell, Regional Performance Manager responsible for all the motorways and trunk roads in the North West, said: "This is going to be a busy weekend for large parts of the region and we are minimising roadworks to ensure we reduce any inconvenience to drivers.
"However, drivers can help themselves by planning their journeys before setting out and ensuring they are prepared for accidents or breakdowns - including ensuring they have enough fuel for their journeys.
"Where possible, drivers who don't have an interest in any of the events might even consider travelling at another time."
To ensure the free flow of traffic, and to cause the minimum disruption to road users and local residents, the following advice has been given:

Avoiding the jams
The majority of the show traffic will be expected to use the M6 and A6 northbound routes to the showground.
Therefore, the key area for avoidance for all traffic not attending the show is J1 M55 Broughton Island between 8am-noon and 4-7pm. Motorists leaving Preston northbound on the A6 towards Broughton Island are advised to use the following alternative routes.
Blackpool/Fleetwood bound: Use the A583 or A5085.
East Lancs area bound: Use A59 or A5085
M6 north bound: Use J31
M6 south bound: Use J31 or 31a
Broughton crossroads will also be congested at the A6/B5269 junction so avoidance of that junction is recommended.

Garstang area
The main access and egress point for the show is situated about half a mile south of Bilsborrow. Congestion will occur for both south and northbound A6 traffic so all traffic not attending the show should avoid this area during the aforementioned times.
All A6 traffic for the show will enter and leave the show at this point.
Congestion is particularly expected at St Michael's due to the mini-roundabout and narrow bridge over the river.
The designated route to the show for traffic from the north is via J33 M6 and the A6, with the main access point to the show half a mile south of Bilsborrow on the A6. Access to the St Michael's road entrance CANNOT be gained for traffic on the A6. However, access to the Guys Court complex and Myerscough College will be permissible.

Parking
Parking is provided within the showground to alleviate the likely congestion. 'No Waiting' cones will be in force on all roads approaching the show and any vehicles found in contravention of these will risk being removed.
Drivers are advised they can check on travel conditions by visiting the real-time traffic information site Traffic England at http://www.highways.gov.uk, ringing the Highways Agency's Information Line on 08457 504030 or tuning in to their local radio station or DAB station Traffic Radio (also available online at http://www.trafficradio.org.uk).
l See next week's Garstang Courier for a free bumper 24 page edition of our monthly Rural Life magazine, including a special preview of the Royal Lancs Show.