Stress levels tend to increase during ordeals where a mistake could lead to a fatality, so my anxiety level was at full throttle when I took my British practical driving test.

I planned to get a British driving licence ever since my family and I moved to London several years ago. I saw it as a way to cut our reliance on trains and buses, but I also saw it as a challenge: I earned the right to drive in Canada and the U.S., but I never learned to drive on the left side of the street, using a right-side steering wheel. To raise the stakes, I signed up to drive standard. After all, why limit yourself to racing Lewis Hamilton when you can add Stirling Moss?

I passed my theory test and booked five hours of practical lessons with AA, thinking that was enough. Americans always seem to think they dont need as many hours of lessons as others, my instructor told me later as we sat in her Ford Fiesta. Maybe that overconfidence had rubbed off on me after so many years in the U.S.

I had a bad feeling the day of my first test as soon as my examiner stormed into the dingy waiting room in the decrepit test center. I knew somehow that I was doomed and, sure enough, he found a way to fault me for one serious error, which is enough to fail (The British first-test pass rate is just under 50%). My mistake? I missed a three-foot-high sign warning stop here ahead of a six-foot-high temporary traffic light.

The signs were symptomatic of one of the biggest speed bumps on the road to adapting to Britain after living in the vastness of North America: Everything is smaller. Streets that might have been laid out long before cars came to the compact country are often too narrow for two-way traffic, intersections come fast and furious, and road signs are everywhere, high and very low. Driving on the left was a low-horsepower challenge by comparison.

I took a crash course (Is that a bad choice of words?) in the days ahead of my second exam with my patient and meticulous instructor, who was big on frequent use of the mirrors and handbrake. I grew nostalgic for stop signs as I negotiated roundabout after roundabout -- some of them tiny -- and pedestrian crossings -- named after birds like pelican and puffin to simplify their titles. Seven hours of extra lessons and much mirror-checking later, there was no looking back.

I had a better feeling about my second examiner. Still, I drove cautiously. I focused on where the next person might dart into the street in overcrowded London. It seemed as if every school group in the city had chosen my exam day to clog the crossings on a field trip. I tried to avoid slamming into a house -- which in London typically comes with a price tag that makes a Bugatti Chiron look like a bargain -- because that would most likely lead to a failing grade. I was mostly penalized for driving too slowly and for undue hesitation, but I passed.

Ive taken a lot of exams, but I dont think any of them have been as stressful as that, I told my examiner. "You were so slow that we were behind a tipper truck and it was outrunning us, she said, and I thought, You can penalize me as much as you want for driving too slowly, just please dont give me a failing grade."

Two weeks later, I had my driving licence. Its good for 10 years, and at the end of that decade Ill probably wonder how North Americans could possibly drive on the right side with automatic transmission.

Learning to drive a car in Britain turned into a way to delve more deeply into traditions and peculiarities of a foreign country. Britain spread its traditions, including the deep-rooted custom of left-hand traffic, to much of the planet over the years, like a Mini on a global road trip. And although most of the world now drives on the right side, I respect the rules of my new home enough to qualify me to steer through Britain as it clings proudly to its own model of exceptionalism.