Dan and Bex are on a road trip. They’re wondering why roads don’t always just go in straight lines.

From the earliest times, taking a straight route between two points hasn’t always been easy.

There may have been natural objects in the way, such as trees, rivers and hills. And today, man made things like other roads, houses and railway tracks might also be in the way!

When a new road is needed, planners have to think carefully about how to get around a range of different obstacles.

They will examine all possible routes to find one which avoids the least number of obstacles. Building roads in a straight line would be ideal – but what if there isn’t a clear straight route without any objects in the way?

Bridges are a simple way to help traffic move in a straight line over obstacles that can’t be moved, like lakes, canals and rivers – and not forgetting railways and other roads!

Although it can be expensive to build a bridge, often it’s cheaper than having traffic going on a long detour.

As well as being as straight as possible, roads need to be as flat and level as possible – not only to help traffic go more quickly but because it’s safer and better for the environment.

So, whilst as fun as it sounds, you won’t find many rollercoaster roads in hilly places! Sometimes engineers will dig a tunnel through a large hill or dig down to create a cutting, using the soil to fill in lower parts so everything is on the level.