Do you know what a "backseat driver" is? 

When my husband and I go shopping, he usually drives and I sometimes make suggestions about how to drive from the passenger seat. He likes to tell me I'm the navigator, but sometimes when I tell him strongly, he tells me I'm a backseat driver and offers to let me drive. :-) 

Today when we drive to the nearby high school grounds to exercise (we try to walk outside once a day for exercise during COVID), I mentioned how to get there faster. Then a fire engine passed us and I saw a real backseat driver! There were actually TWO drivers, one in the front of the long fire engine AND ONE IN THE BACK! 

https://www.fireapparatusmagazine.com/fire-apparatus/video-eone-super-tiller/#gref

A fire engine with a "back seat" driver is said to have a "tiller." 

Here's a video of a fire engine with a tiller and back seat driver in action:

https://youtu.be/N7D_HgTBst8

So next time someone calls you a back seat driver, just ask, "Where's the fire!"