Presentation of the NVF paper at HVTT11 in Melbourne 2010.

1. Reducing Health and Safety Risks
on Poorly Maintained Rural Roads
Johan Granlund, MSc, IPMA B
Chief Technology Officer
Vectura Consulting AB, Sweden

2. Lateral forces and low / split friction
really don´t mix well
[Photo: Torbjörn Elverheim] [Photo: Niclas Thunborg]
Instability crashes
are not randomized.

3. The paper in a nutshell
Disproportionate risk on rural low volume roads.
NVF statement on need of actions to mitigate over-risks.
Health and safety issues raised by high ride vibration.
Roadex-project case study on the Beaver Road 331.
Identifying road features decisive for risk factor such as:
• lateral force,
• poor road surface drainage, and
• low friction; often in combo with split friction,
using available data from road profilers.

4. Disproportionate risks in
the rural EU Northern Periphery
153 % higher risk to die in a vehicle crash in rural NP areas,
than in metropols Stockholm, Gothenburg & Malmoe.
[Photo: Torbjörn Elverheim]
NP road crashes take 39 % more lives than the worst
therapeutically treatable “big killer” Diabetes Mellitus.
Truckies 3 times higher prevalence of heart disease.

5. Nordic Road Association Statement
“-There is a need to implement new knowledge and
practical methods into new approaches, aiming to
make an efficient reduction of the disproportionally
high health and safety risks on hot spot sections on
the road network.
This will improve the working environment for
professional drivers and is expected to reduce crash
risk for both heavy vehicle and light vehicle traffic as
well”.
NVF Working Group on Vehicles and Transportation
Helsinki 2010-02-02

6. Health and safety issues
raised by ride vibration
Road Feel Driver’s Performance
Vibration Driver Response Accident Potential
Vehicle Performance
Driver/Vehicle
Ride Excitation Ride Environment Driver Response Accidents
Performance
Low Level, Physical (Biodynamic) Potentially Influenced by
Multi-Modal Vibration Driver
Distributed Response – Vibration of
Roughness - Visual Acuity -Prefatigue Vigilance
Severe, Dominant Frequencies Body Parts and Organs
Localized 1 to 10 Hz - Reaction Times
Physiological Effects - Fatige-decreased Vigilance
- Tracking and other
Frequency Dominant Amplitudes
eg. Visual Motor Tasks -Drivers’ Modulation of Steering
Speed Influence up to 2 m/s2
Cardiovascular and Brake Controls
Amplitude
Rattling Control Vehicle - Driver Affected by Ailments
Vehicle has: Instruments and Mirrors Psychological Effects
eg. Discomfort - Road Holding - Image Clarity in Mirrors
• Variable Payload
Possible Momentary Stress - Component Wear
• Stiff Suspension -”Unseated” Driver by Severe Jolt
”Unseating” of Driver - Component Failure
• Dry Friction in the Springs Pathological Effects
- Vehicle Road-Holding
• Flexible Frame eg. Back Pain
Performance
• Multiple Coupled Masses
• Rotating Nonuniform Components
[Highway Safety Research Institute]

7. 2002/44/EC
Physical Agents Directive - Vibration
If the truck drivers exposure exceeds the Action Value
A(8)= 0.5 m/s2, the employer is obliged by law to
take measures to minimize vibration exposure.

8. EU Roadex III project
case study on the Beaver Road 331
A regional 170 km route across Västernorrland, Sweden.
Annual Average Day Traffic, AADT, 350 to 2000 veh/day.
Speed limits 90 and 70 km/h.

9. Mounting truck ride sensors
Test truck Scania R480 164 G 6x4, GVW 60 ton incl trailer.
Z-axis 1 kHz at L and R frame and at
front wheel axle.
GPS + 6-axis 100 Hz
inertial unit in the cab.
X, Y, Z-axis 1 kHz seat pad.
Camera for right of way.
Mic for interior noise.

10. Daily Vibration Exposure A(8)
Daily vibration exposure A(8) Scania R480G 6x4 timber logging truck
Route, 8 h morning shift: Ramsele - Backe (unladen), Forest Road, Backe - Stavre - Ortviken
(loaded), Ortviken - Backe (unladen), Backe - Ramsele (loaded) and some misc driving.
0,90
0,76
0,80
0,70
0,60
Vibration [m/s2]
0,50
0,50
Current exposure
0,40 EU Action Value
0,30
0,20
0,10
0,00
Results for normal driving shifts, taking roundtrips from
the Forests to the Coast:
A(8) = 0.76 m/s2, over EU Action Value A(8) = 0.5 m/s2.

11. Reference road measurement
[Photo: Mats Landerberg]
• Road alignment (curvature, grade, cross slope),
• roughness,
• texture, and more.

12. Truck seat vibration vs road roughness
Truck seat vibration intensity @ 75 km/h:
RMS(ax,y,z) = 0.18 + 0.30 * IRI
Zero vibration (0 m/s2) during 100 min loading & pauses.
Maximum road roughness for 380 driving min / day,
without exceeding the Action Value A(8) = 0.5 m/s2:
IRI < 1.27 mm/m, a challenge on low volume roads!
Recommended minimum short-term action:
Seek to eliminate local road damage causing IRI20m higher
than 3 mm/m, as well as steps at road/bridge joints and
potholes causing Megatexture1m over 0.60 mm.

13. Quasi-static lateral forces:
-Too sharp curves with insufficient outer
banking

14. Side friction demand is used when
designing curve superelevation
ν2
≈ tan(α ) + f s
R*g
[Swedish Vägverket, VGU]
[Norwegian Statens Vegvesen, Håndbok 111]
[UK Design Manual for Road s and Bridges ]
Side friction demand can also be used as a control
measure for instability risk in existing curves, using
measured data on curvature and cross slope!

15. Example side friction demand
in a fatal rural curve
5 crashes within 45 m,
2 of them were fatal Excessive friction demand
Pitfall: Many road design codes use too high side friction
supply factors, overseeing the higher side friction need
of long vehicles driven with large slip angles.

16. Transient lateral forces on
roads without a strong shoulder:
-Deformed pavement edge, due to insufficient
lateral support

17. Rut Bottom Cross Slope Variance
-predicting truck roll and lateral buffeting
Cause to
Rd 331, Ramsele - Ärtrik
Variance of Truck Cab Roll Angle vs Variance of Cross Slope
difference at
HS Åkerö edge damage at 125 275 m
1,2
HS Åkerö 1,0
seen on next 0,8
Variance
slide
0,6
0,4
0,2
0,0
126400 126200 126000 125800 125600 125400 125200 125000
RDB distance [m]
Variance of truck cab roll angle Pavement RBCSV
Photo: Max Risberg
Read the paper for details on RBCSV calculation, draft
limit and correlation with hazardous sites.

18. 3D laserscan at HS Åkerö
Note: Exploded truck tire
A 69 mm deep deformation

19. Insufficient drainage gradient (DG)
-Hot spots located at entrance/exit
of banked outercurves.
i
Right hand traffic Left hand traffic
E DG = √ ( i 2
+
E 2)
DG being lower than 0.5 % is one of the key causal
factors behind the fact that outer curves show 5
times higher rate in fatal crashes!

20. Many new road construction projects
has a built-in skid risk:
- Insufficent drainage gradient
Rd 90, Rödsta - Näsåker
Skid risk: If the Drainage Gradient doesn´t exceed 0.5 %, water pools will be formed
6,0 3,0
5,0 2,0
Curvature = 1000 / Radius [m]
4,0 1,0
Gradient [%]
3,0 0,0
2,0 -1,0
1,0 -2,0
Photo: High Coast Rescue Dept
0,0 -3,0
0 2000 4000 6000 8000 10000 12000
Distance [m]
Drainage Gradient Unacceptably low Drainage Gradient Curvature
12 risk sections with DG lower than 0.5 % in a 12 km long new road.
All risk sections located at entrance/exit of banked outercurve.

21. Curve with 5 crashes within 2 weeks?!?
Improper asphalt patching gave extreme crash
outcome when raining just after the road work.
[Photo: Bengt Andersson]

22. Patch with low texture
gave severe Split-friction
Rv 61, Åmotfors - Kristinehamn
Vägbanans makrotextur (ytskrovlighet)
Avgörande för våtfriktion samt hastighetsberoende del av friktionen
Olycksplats 10/9 vid distans ca 4680 m (- upp till ca 200 m)
3,0
2,5
2,0
Textur [mm]
1,5
1,0
0,5
0,0
4300 4350 4400 4450 4500 4550 4600 4650 4700
Distans [m]
MPD Vänster MPD Mitt MPD Höger
A 66 m long ”fat” patch in the near roadside wheelpath.
Patch texture far below intervention level ”Minimum 0.6 mm”.
This equals having slick worn tires on one side of the vehicle.

23. Summarizing the paper
NVF statement on the need of actions to mitigate
disproportional health and safety risk.
Roadex III project case study on the Beaver Road 331.
Identifying road features decisive for risk factor such as:
• Ride vibration and shock,
• lateral force,
• poor road surface drainage, and
• low friction; often in combo with split friction.
Analysis based on available data from road profilers.