It’s a similar story further down on Peninsula Link southbound, between 11am and 2pm, when it appears thousands of motorists decide to take a trip to the seaside at the exact same time.

Boxing Day has the worst seaside-direction congestion, but during the dying days of December, southbound travel speeds in these areas snap back to the average. Maybe it’s because most people want to maximise the amount of time they spend down the coast and get out Melbourne at the earliest opportunity.

The only other time of year these roads experience such a drop in travel speeds is at the start of the Australia Day weekend, so it pays to leave early in the morning if you’re travelling down the coast.

VicRoads estimates traffic can surge in some areas by almost 20 per cent over the holiday season, and they are using data from previous years to plan for all those bargain hunters and holidaymakers on the roads.

The road authority’s own data shows traffic volumes drop during the morning and evening peak during school holidays, but there are more cars on the road on average during the middle of the day and in the evening.

Travel speeds around major shopping centres plummet on Boxing Day because of all the people flocking to sales, but the HERE data shows this type of congestion should ease for the rest of the week.

For example, if you were driving down Dandenong Road at noon on Boxing Day you would likely be crawling along at 15 km/h on your approach to Chadstone Shopping Centre.

But if you were to venture down that same stretch at that time on Thursday, your car would probably be able to cruise by at 50 km/h, which is the average speed on a normal day.