I’ve written here before about the joy and peace I feel when I head into the mountains that form a brow over Los Angeles, but haven’t mentioned the number of interesting people I share them with.

There are other road cyclists like me of course, some alone, others in matching team jerseys doing fast hill repeats. Mountain bikers—that whole other species of cyclist—can be seen gathering at trailheads or appearing suddenly from paths no wider than them and their bikes.

Our two-wheeled cousins, the motorcyclists, are up here all the time. Sometimes it’s Harley riders, but usually out here on the winding roads it’s the sports motorcyclists in full leathers, rounding curves at breathtaking speeds, their knees almost touching the ground. Considering how much I love motorcycles, I’m surprised at how violent these machine seem out here, hearing them many minutes before they scream past me, the smell of exhaust and hot rubber following them like an evil wedding dress train.

Then there are the sports car drivers in convertibles old and new, tricked out Japanese hot hatches, Italian exotics and sometimes, hot rods. Two Polaris Slingshots passed me the other day—the three-wheeled machines that are part motorcycle, part car and whose promotional videos seem to have been shot on the very roads I ride on. Once, I got in the way of another car video being shot by a drone—the first time I’ve seen one of these in action.

My least favourite mountain road users are the off-road vehicle drivers. Those knobbly tyres and high suspensions seem to make for aggressive and impatient driving, so I’m happiest to spy on them from high above as they grind and swirl in the dusty riverbeds.

It’s not all engine roar and smoke though. Recently, an artist had an easel up, painting a beautiful, realistic rendition in oils of the dramatic dam along Highway 39. I often pass hikers and birders walking to trails or back to their cars. And at its simplest, groups of young friends stop their cars and gather round views, talking and laughing.

The strangest most startling denizens of the mountain are the downhill longboarders. Imagine standing at the top of curving road and stepping onto a skateboard to race downhill at speeds in excess of 60km/h.

When I was first on the Glendora Mountain Road (or GMR as it’s known here) on weekdays, I’d be terrified by a sudden scraping sound, and the appearance of a helmeted young person sometimes in full leathers, crouching on a giant skateboard, using “slide gloves” to push on the ground to urge the board around the corner. I couldn’t fathom how they slowed, and most importantly, how they came to an emergency halt.

Being a trusting person, I assumed the sport was safer than it looked, but have since understood it’s every bit as wild as you’d think. Sadly on March 20, a young longboarder was killed on GMR after crossing the yellow line and crashing into a truck. Looking at a picture online, it was “grey helmet” who I’ve seen many times.

For a lot of us, being on those mountains is about pushing ourselves. Those motorcyclists don’t need to corner so fast their knees touch the ground. Those road cyclists are mad to enjoy the sweaty huffing climbing as much as the descending. And as for the longboarders, if it was written that Grey Helmet had to go so young, I’m glad he was on his skateboard on the mountain, and not, as is so often the case, in a car on one of the freeways in the valleys below.

Gautam Raja is a freelance journalist based in Los Angeles, USA.