It was November 1 and my son Lawrence was 11 years old. We were having our Ofsted inspection so it was quite a stressful time, everything felt hectic. Lawrence was late and left the house at about 8.15am. We've lived on a main road since 1987 and we've always taught our kids how to cross the road safely. But the traffic was backed up outside the house. Lawrence dived out and dodged between the queuing cars. He ran for the bus but he hadn't seen a car in front of it. He died instantly.
The first I knew about it was a neighbour and my daughter's friend at my back door. They just kept on saying, "I'm so sorry." I have no recollection beyond that. Lawrence only had a small cut on his forehead, but his neck was broken. I collected all the buttons from his shirt and put his shoes neatly by the side of the road. I was strangely calm. I said to the paramedic, "I can't cry", and she said, "Don't worry, you will." It took weeks to compute what had happened. I knew Lawrence was dead but I had no idea of the intensity of such grief.
My headteacher came to see me that same day. That must have been hard for her. She was usually so businesslike, but she showed such compassion and gave me valuable advice. I took six months off; our priority was to learn to live and cope as a family and not just exist. Even though I was 41 my husband and I decided to try for another child, not as a replacement but to make a positive difference for us all. When I came back to work in April, I was pregnant, and Ciaran was born in October.
I thought I was invincible, but the reality check of school life meant I had to find new coping strategies. We have tough inner-city kids at my school, but they can be enormously loving.
I can't say I didn't have thoughts about dying. That Christmas, I told my husband I couldn't see how I could live and he said: "How do you think I feel?" That stumped me - it was OK for me to feel that way, but I didn't want him to.
The turning point came about a month later when I was speaking to a mother who had lost her 16-year-old daughter. I asked when it starts to get better, and she said, cheerfully: "It won't; you're an empty shell waiting to die."
Something clicked then. I felt sorry for her, but I wanted to be a good mother and a wife. Selfishly perhaps, I didn't want to live an empty life. I knew Lawrence would have been sorry for making a mistake and wouldn't want me to be sad. I decided then that something good would come of this, that his death wouldn't be in vain.
When children have near misses with vehicles at school, the head tells them to be careful but I see their eyes glaze over. I've stood up impromptu in assembly and told them my story. Or we've looked at speed ads in class and I've shown them a picture of Lawrence. Once they've made the connection, they look horrified.
Ten years later, the depth of my grief still surprises me. Just the other week, I was covering an RE lesson and they were watching a film about the afterlife. I was surprised at my sudden emotion. I explained to the class that I have been to the funeral of my son. They watched it with a greater sense of gravitas after that and I thanked them for their dignity and respect.
My husband thought I'd go to pieces after the accident but I've found strength I never knew I had. I would have loved Ciaran to have experienced his brother's love, but I know he has a loving family because of Lawrence.
Helen Hammond is an art teacher at Mount St Mary's Catholic High School in Leeds. She was talking to Hannah Frankel. Visit www.brake.org.uk. If you have an experience to share, email email@example.com.