04/12/2013 07:34 GMT | Updated 02/02/2014 05:59 GMT

Getting Hit by a Mack Truck

Seventeen days out, over the Arizona border at Needles, and my fate is chasing me.

I'm staying in a motel in the small California town, and a helpful gent has given me a lift to the location of the bridge where the Joads crossed in the 1940 film version of The Grapes of Wrath. A fictional trek based on reality and referenced several times by me in Dear Miss Landau.

We pull over onto the hard shoulder of the Interstate, jog-trot back to the centre of the bridge over the Colorado river and get several photos of the sign denoting California's state line.

The place they crossed. The place I crossed.

I'd never seen it before. I'd been going the other way in 1989, my mind was on different matters in 2010 (how to live up to meeting with Juliet Landau), and I just plain missed it in 2012.

Not this time, though.

We traverse the border line several times, photograph "Joads bridge" and snap off shots of the state line and border signs.

It's only on the way back to the car that my companion mentions that a Mack truck just veered a bit and drove over the spot we'd been standing on only a minute before.

My mind goes back to a quip I made in Dear Miss Landau.

"I'll try not to get hit by a Mack truck..."

It was jest but also metaphor. Soldiers assume there's some bullet out there with their name on it. Travelers like me know that however carefully we prepare, events can overwhelm them. Although Dear Miss Landau and these blogs were written to inspire people with autism, risk cannot be eradicated from life and if there is one lesson I must deliver from my meticulously-planned progress across this continent, it is that though I may be as lucky as one of Napoleon's generals, I could still get myself killed.

James Christie is the author of Dear Miss Landau. He was diagnosed with Asperger Syndrome, a mild form of autism, at the age of 37 in 2002. He lives in the Scottish Borders.