New York State Snowmobile Trail Signing Handbook - 6

SIGN POSTING DISTANCES
What is the proper distance before an object
to place a warning sign? There are several factors
involved in calculating the minimum posting
distance including:
* Speed of the snowmobile when the sign is
initially visible to the operator
* Sign legibility or recognition
* Decision making time
* The coefficient of friction between the track
and snow
* Comfortable braking distance
The table below offers some guidance on
what the appropriate sign posting distances
should be. These recommendations have been
developed through a variety of snowmobile and
traffic publications, including the Manual on Uniform
Traffic Control Devices and field observations. The
minimum sign posting distances recommended
below pertain only to cautionary signs.
TABLE 1 - Cautionary Sign Placement
Suggested Minimum Posting Distances for Snowmobile Cautionary Signs (in feet)
Judged Speed (mph) Condition Requiring Stop " X " = Example - Deceleration Distance to Desired Speed of 20 mph
20 *
25 *
30
35
40
45
50
55
175
225
300
350
425
500
100
175
250
300
400
475
* No suggested minimum distance recommended. At these speeds, sign location depends on physical conditions at the site.
The sign posting table looks at two situations.
The first is a situation where a cautionary sign
is posted so that a snowmobile can come to a
complete stop before the trail condition. The most
common example of this situation would be a
" Stop Ahead, " trail sign prior to a STOP sign. The
second signing situation is one where a SLOW
sign is posted so that a snowmobiler might have
to reduce speed, but not necessarily come to a
complete stop. Examples of this situation might
be changes in trail direction. The intent of warning
signs is to allow the snowmobile to be brought
to a complete stop before the trail condition. In
some cases, a complete stop is not necessary,
but we suggest the posting distance be sufficient
for a complete stop in the event it is necessary.
The key factor in using the following table
is the judgment of the signing crew on what the
speed of the majority of reasonable snowmobilers
in that situation would be and what reduction
in speed, if any, would be necessary for the
snowmobiler to comfortably and safely negotiate
the trail condition.
The Table above shows a range of distances
for trail sign placements. The Table is adapted
from IASA Signing Guidelines and is intended as
a general guide for sign placement distances.
6
Most snowmobile trails typically have a mix of
trail surface conditions and those conditions can
change daily depending upon weather conditions
and other factors. Terrain and trail conditions also
have to be taken into account.

New York State Snowmobile Trail Signing Handbook

Table of Contents for the Digital Edition of New York State Snowmobile Trail Signing Handbook