The cameras have been installed and configured on the northern part of the A675 at Belmont, from the M65 junction 3 to north of Belmont Village.
The short remainder of the route through Belmont to Scout Road, will be finished this summer with a go live date yet to be set.
Further information will be shared ahead of this.
This is the second of eight routes across the county to be enforced, while installation is on-going or yet to begin on the remaining roads throughout Lancashire.
The Lancashire Road Safety Partnership (LRSP) gave the go ahead for the scheme last year and in January announced the chosen routes in a bid to reduce road casualties and collisions.
The Partnership decided to adopt the system using average speed cameras as safety and motorist compliance has consistently improved on a variety of road types using the system in other parts of the UK.
The cameras will use number plate recognition technology to detect vehicles and calculate their average speed by measuring the time taken to travel between fixed points of a known distance apart. Average speed check signage will be used to inform drivers that they are entering an average speed control zone.
A police spokesman said: “ The introduction of the system is intended to positively influence driver behaviour and ensure that motorists comply with the set limits on roads, resulting in a safer environment for all road users.
“There will be sanctions for anyone detected breaching the speed limits, where eligible they will be given the opportunity to attend a speed awareness course to learn about the dangers of speeding, accept a conditional offer of a fixed penalty (currently £100 and 3 penalty points) or for higher speeds the matter may be referred to court.”