Fatal
Serious
Slight
Uncategorised
| Date | Local Authority | Vehicles | Casualties | Severity |
|---|---|---|---|---|
| Sun 5 Jan 1986 | Stevenage | 1 | 1 | Serious |
| Sat 18 Jan 1986 | North Hertfordshire | 2 | 1 | Slight |
| Wed 22 Jan 1986 | East Hertfordshire | 1 | 1 | Slight |
| Wed 22 Jan 1986 | North Hertfordshire | 2 | 1 | Slight |
| Tue 28 Jan 1986 | East Hertfordshire | 1 | 1 | Slight |
| Fri 31 Jan 1986 | Stevenage | 2 | 1 | Slight |
| Mon 10 Feb 1986 | North Hertfordshire | 2 | 1 | Slight |
| Mon 10 Feb 1986 | Stevenage | 1 | 1 | Slight |
| Tue 11 Feb 1986 | Stevenage | 1 | 1 | Slight |
| Wed 12 Feb 1986 | Stevenage | 2 | 1 | Slight |
| Sun 16 Feb 1986 | Stevenage | 1 | 1 | Serious |
| Mon 17 Feb 1986 | Stevenage | 1 | 1 | Slight |
| Fri 21 Feb 1986 | North Hertfordshire | 2 | 1 | Slight |
| Sat 22 Feb 1986 | Stevenage | 1 | 1 | Slight |
| Sat 22 Feb 1986 | East Hertfordshire | 2 | 3 | Slight |
| Thu 27 Feb 1986 | East Hertfordshire | 1 | 1 | Slight |
| Tue 4 Mar 1986 | Stevenage | 2 | 1 | Slight |
| Tue 4 Mar 1986 | Stevenage | 2 | 1 | Slight |
| Wed 5 Mar 1986 | Stevenage | 2 | 1 | Serious |
| Thu 6 Mar 1986 | Stevenage | 1 | 1 | Serious |
| Sat 8 Mar 1986 | East Hertfordshire | 2 | 1 | Slight |
| Sun 9 Mar 1986 | East Hertfordshire | 3 | 1 | Slight |
| Wed 12 Mar 1986 | Stevenage | 3 | 2 | Serious |
| Wed 12 Mar 1986 | Stevenage | 1 | 1 | Slight |
| Sat 22 Mar 1986 | North Hertfordshire | 2 | 2 | Slight |
| Tue 25 Mar 1986 | Stevenage | 2 | 2 | Slight |
| Tue 25 Mar 1986 | Stevenage | 2 | 2 | Slight |
| Fri 4 Apr 1986 | Stevenage | 2 | 1 | Slight |
| Sun 13 Apr 1986 | Stevenage | 1 | 2 | Slight |
| Thu 17 Apr 1986 | Stevenage | 2 | 1 | Slight |
| Sat 19 Apr 1986 | East Hertfordshire | 1 | 1 | Slight |
| Mon 21 Apr 1986 | North Hertfordshire | 2 | 1 | Slight |
| Sun 27 Apr 1986 | Stevenage | 1 | 1 | Slight |
| Sun 27 Apr 1986 | Stevenage | 1 | 1 | Slight |
| Mon 5 May 1986 | Stevenage | 1 | 1 | Slight |
| Wed 14 May 1986 | Stevenage | 2 | 1 | Slight |
| Thu 15 May 1986 | North Hertfordshire | 1 | 1 | Serious |
| Thu 15 May 1986 | Stevenage | 1 | 2 | Slight |
| Sat 17 May 1986 | East Hertfordshire | 1 | 2 | Serious |
| Mon 19 May 1986 | North Hertfordshire | 2 | 2 | Slight |
| Thu 22 May 1986 | Stevenage | 2 | 2 | Slight |
| Wed 11 Jun 1986 | North Hertfordshire | 2 | 1 | Slight |
| Mon 23 Jun 1986 | Stevenage | 1 | 1 | Slight |
| Wed 25 Jun 1986 | Stevenage | 2 | 2 | Slight |
| Sun 29 Jun 1986 | Stevenage | 2 | 5 | Serious |
| Sat 5 Jul 1986 | North Hertfordshire | 2 | 2 | Slight |
| Wed 9 Jul 1986 | Stevenage | 2 | 1 | Serious |
| Fri 11 Jul 1986 | Stevenage | 1 | 1 | Serious |
| Fri 11 Jul 1986 | Stevenage | 1 | 1 | Slight |
| Tue 15 Jul 1986 | East Hertfordshire | 3 | 1 | Slight |
| Wed 16 Jul 1986 | East Hertfordshire | 2 | 2 | Serious |
| Mon 21 Jul 1986 | North Hertfordshire | 2 | 1 | Serious |
| Thu 24 Jul 1986 | North Hertfordshire | 2 | 1 | Slight |
| Fri 8 Aug 1986 | Stevenage | 1 | 2 | Serious |
| Sat 9 Aug 1986 | Stevenage | 1 | 1 | Serious |
| Tue 12 Aug 1986 | North Hertfordshire | 3 | 1 | Slight |
| Sat 16 Aug 1986 | East Hertfordshire | 3 | 1 | Slight |
| Mon 18 Aug 1986 | Stevenage | 1 | 1 | Slight |
| Wed 20 Aug 1986 | Stevenage | 1 | 1 | Slight |
| Sun 31 Aug 1986 | Stevenage | 1 | 1 | Slight |
| Sun 31 Aug 1986 | Stevenage | 1 | 1 | Slight |
| Mon 8 Sep 1986 | Stevenage | 1 | 1 | Serious |
| Mon 15 Sep 1986 | Stevenage | 2 | 1 | Slight |
| Mon 15 Sep 1986 | Stevenage | 2 | 1 | Slight |
| Wed 17 Sep 1986 | East Hertfordshire | 1 | 1 | Slight |
| Wed 17 Sep 1986 | East Hertfordshire | 2 | 1 | Serious |
| Mon 22 Sep 1986 | East Hertfordshire | 1 | 1 | Slight |
| Tue 23 Sep 1986 | North Hertfordshire | 1 | 1 | Serious |
| Tue 14 Oct 1986 | East Hertfordshire | 5 | 1 | Slight |
| Fri 17 Oct 1986 | North Hertfordshire | 4 | 2 | Serious |
| Sun 19 Oct 1986 | Stevenage | 2 | 1 | Slight |
| Sat 1 Nov 1986 | Stevenage | 1 | 1 | Serious |
| Sat 1 Nov 1986 | Stevenage | 1 | 1 | Serious |
| Sat 1 Nov 1986 | Stevenage | 2 | 1 | Serious |
| Sat 1 Nov 1986 | Stevenage | 2 | 1 | Serious |
| Fri 7 Nov 1986 | Stevenage | 1 | 1 | Slight |
| Sat 8 Nov 1986 | North Hertfordshire | 2 | 1 | Slight |
| Sun 9 Nov 1986 | Stevenage | 2 | 1 | Slight |
| Wed 12 Nov 1986 | Stevenage | 2 | 1 | Slight |
| Wed 12 Nov 1986 | North Hertfordshire | 3 | 4 | Serious |
| Thu 13 Nov 1986 | Stevenage | 1 | 1 | Slight |
| Wed 19 Nov 1986 | North Hertfordshire | 3 | 1 | Slight |
| Thu 20 Nov 1986 | North Hertfordshire | 3 | 3 | Fatal |
| Tue 2 Dec 1986 | Stevenage | 1 | 1 | Slight |
| Wed 3 Dec 1986 | East Hertfordshire | 1 | 4 | Serious |
| Mon 8 Dec 1986 | East Hertfordshire | 2 | 1 | Slight |
| Wed 10 Dec 1986 | North Hertfordshire | 2 | 1 | Slight |
| Thu 18 Dec 1986 | Stevenage | 2 | 1 | Slight |
| Tue 23 Dec 1986 | Stevenage | 1 | 1 | Serious |
| Tue 30 Dec 1986 | East Hertfordshire | 3 | 1 | Slight |