Excerpts from the 1998 Study
by Dynamic Research Inc, USA

Accident trends
Accident trends were investigated for the relative safety of motorways compared to all roads, single versus tandem riders, and single versus tandem riders on motorways. Numbers of accidents and exposure data and resulting rates for several industrialized countries or regions are tabulated in Appendix B, based on datas found in Refs 1 to 3 and 5 to 22. The findings from these analyses are described below.

a. Motorway Accident Trends.
The accident, injury and fatality rates listed in Tables 1 and 2 indicate that motorways in Denmark, France, Germany, Great Britain, Ireland, Switzerland and the United States are much safer than non-motorways in these countries, for all motor vehicles, as well as for passenger cars and motorcycles, where those data are available. The ratio of non-motorway to motorway involvement rates in the 7th column of Table 1 is a measure of the relative safety of the motorways. These results indicate that motorways in general are 3 or more times safer than non-motorways in these countries. For Japan, based on available statistics, motorways are 13 times safer than non-motorways for all motor vehicles.

The relative safety of motorways applies to "motorcycles" as well as "passenger cars" and "all motor vehicles", as indicated by the more detailed rates for Great Britain and the US in Table 1. Specifically, for motorcycles, motorways are 5 times safer than non-motorways in the US and 6 times safer than non-motorways in Great Britain.

The number of accidents, injuries, and fatalities in France, Germany, Great Britain, Japan and the US were also greater on non-motorways than on motorways, regardless of exposure and vehicle type. The incidence ratio listed in the 7th column of Table 3 indicates that accidents, injuries, and fatalities are 8 or more times more likely to occur on non-motorways than on motorways. Again this relative safety trend applies to motorcycles as well as to passenger cars and all motor vehicles. For example, for motorcycles. In terms of absolute numbers, motorways are 13 times safer than non-motorways in the US, 112 times safer than non-motorways in Great Britain and 8 to 28 times safer than non-motorways in Hannover, Germany.

B. Tandem Rider Accident Trends.
Tandem rider accident, injury, and fatality rates per vehicle exposure is generally less than or equal to that of single riders. as indicated by the data for the United States; Los Angeles; and Berkshire County, United Kingdom listed in Table 4.

Note in Table 4 the the 2.0 tandem rider fatalities per 100 million tandem rider vehicle miles on motorways in the United States is 6 times safer than the corresponding fatality rate for single riders on motorways; and 9 times safer than the corresponding fatality rate for tandem riders on non-motorways. These results simply indicate the relative safety of tandem riding on motorways.

Considering personal exposure, tandem rider injury and fatality rates per person exposure is generally 1.7 or more times safer than the rates for single riders, according to the results for the US and Berkshire County, UK, listed in Table 4. The relative safety of tandem riding on motorways in the United Stataes is even more dramatic (ie, 12 to 1) when considering person-miles traveled.

Table 1. Motorway Vs Non-Motorway Involvement Rates

Region	Measure	Vehicle Type	Rate Motorways	Rate non-motorways	Rate All roads	Incident Ratio non-mw to mw
France 1991	Num. killed/ 100 million vehicle hours	All motor vehicles	0.91	3.3	-	4 to 3
	Num. injured/ 100 million vehicle hours	All motor vehicles	9.9	30.5	-	3 to 1
Germany 1993	Injury accidents/ 100 million vehicle kilometers	All motor vehicles	15	-	64.5	-
Great Britain 1987	Num. fatalities/ 100 million vehicle kilometers	All motor vehicles passenger cars motorcycles	.6 - -	1.8 - -	1.6 0.9 14.2	3 to 1 - -
	Num. casualties/ 100 million vehicle kilometers	All motor vehicles passenger cars motorcycles	19 - -	113 - -	98 62 896	6 to 1 - -
	Num. involved vehicles/ 100 million vehicle kilometers	All motor vehicles passenger cars motorcycles	25 25 168	150 125 958	131 112 920	6 to 1 5 to 1 5 to 1
Japan 1995	Num. fatalities/ 100 million vehicle kilometers	All motor vehicles	-	-	1.5	-
	Num. injured/ 100 million vehicle kilometers	All motor vehicles	-	-	131.1	-
	Num.accidents/ 100 million vehicle kilometers	All motor vehicles	10.1	125.9	108.2	13 to 1
United States 1996	Num. fatalities/ 100 million vehicle kilometers	All motor vehicles passenger cars motorcycles	- 0.5 3.5	- 1.1 15.9	1 0.9 15.8	- 2 to 1 5 to 1

Table 3 Motorway Vs Non-Motorway Involvement Numbers

Region	Measure	Vehicle type	Count Motorways	Count non-motorways	Count All roads	Incident Ratio non-mw to mw
France 1991	Num. killed -rural roads	all motor vehicles	600 400	9,882 6.169	10,482 -	16 to 1 -
	Num. injured -rural roads	all motor vehicles	8,785 4,328	197,183 61,319	205,968 -	22 to 1 -
Hannover Germany 1985 - 1996	Num. of fatalities	motorcycles	4	31	35	8 to 1
	Num. of Injured	motorcycles	46	1,241	1,287	27 to 1
	Num. of accidents	motorcycles	44	1,237	1,281	28 to 1
Germany IF/GDV data	Num. of fatalities	motorcycles	1	49	50	49 to 1
	Num. of Injured	motorcycles	5	630	635	126 to 1
	Num. of accidents	motorcycles	4	592	596	148 to 1
Great Britain 1987	Num. of fatalities	All motor vehicles Passenger cars Motorcycles	283 - -	4,482 - -	5,125 2,206 723	17 to 1 - -
	Num. of casualties	All motor vehicles Passenger cars Motorcycles	9,080 - -	302,393 - -	311,473 159, 468 45,801	33 to 1 - -
	Num. of vehicles	All motor vehicles Passenger cars Motorcycles	12,021 8,885 311	402,967 278,751 34,722	414,988 287,636 35,033	34 to 1 31 to 1 112 to 1