Dear Albert O'Neill

I did in Finland during year 1996 very short survey of water spray effects
with fatal accidents recorded and investigated in Finland between years
1987-1994 (so quite long ago)

The original report was very short (and in Finnish!), but based on that I
try shortly to answer few of your questions

> 6.      What are you views on the benefits of using spray suppression
devices?

Traffic safety improvement espacially during over taking. Also environmental
positive effects via reduced need of washing (heavy) vehicles and preventing
water spraying from the road sides.

> 7.      What are the negative aspects of using spray suppression devices
(or
> reasons for not using them)?

Increased weight, possible increase into air resistance, danger of large
slush / ice lumps to be produced near freezing point

> 9.      In your view, what are the negative consequences of splash and
spray
> (which is unsuppressed), and which road users are most affected?  Is it a
> real safety hazard or an inconvenience?

In certain driving situations and locations it is a real danger. What comes
to cleaning etc. it is question of inconvenience. In city / urban area also
pedestrians and cyclists can have a significant benefit from water spray
reducing devices (especially in busses). In busses / heavy vehicles also the
advertisements can be kept cleaner a longer period.

> 10.     Are you aware of any statistical information or reports on
accidents
> caused by (or attributed to) spray from heavy vehicles?

In Finland between years 1987-1994 (years included) in fatal accidents (all
fatal accidents are investigated in Finland by a special committees)

- bewteen years there were 3323 fatal accidents
- in those accedents died 4045 and injured 3268 people
- in those accidents were 7 accidents with partisipation of water / slush
spray.
- with these 7 accidents were 8 people killed and 16 injured (10 injured
were in one single accident including a bus)
- so it can be estimated that water spary was involved in 0,21% of fatal
accidents.

This internal report was done in Helsinki Univeristy of Technology,
Laboratory of Automotive Engineering for the Traffic Safety Committee of
Insurance Companies (VALT).

From the accident recordrs with no fatal consequencies, it was not possibel
to estimate water spary effects.

> 12.     Do you have any other comments or suggestions you wish to make
> regarding the use of spray suppression devices?

There are also possibilities to affect water spray with the quality of
pavement (porous asphalt etc.). That would effect for all vehicles in that
road section immediately. (and would be quite expensive). Some private motor
way companies in France advertise if I remember right that kind of
properties of their roads also.

Spray suppression deceives can be effective if done properly. The better
aerodynamics of the vehicle can also be very effective method to control
water spray (positive effect can also be reduced fuel consumption depending
of the drive cycle).

Best regards

    Panu Sainio


Panu Sainio M. Sc.(Tech)
Helsinki University of Technology
Ground Vehicle Engineering
tel work xx 358 (0)9 451 3464
fax work xx 358 (0)9 451 3469
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mobile xx 358 (0)50 5678 396