Greek Guidelines for Setting Speed Limits. Presented at the Road Safety and Simulation Conference 2007

1. GREEK
GUIDELINES FOR
SETTING SPEED
LIMITS
B. Psarianos, S. Palaskas, Nat’l Techn. Univ. Athens, Greece
N. Stamatiadis, Univ. of Kentucky, U.S.A.

2. SPEED LIMIT?

3. Speed Limit: It’s a Problem
See this Example
Design Speed = Operating Speed = 85% Speed (as of December 2005)
On the TANGENT:
•Passenger Cars: 144 km/h in the driving middle lane (3.50m) –VIOLATION 24 km/h
•SU Trucks: 89 km/h in the driving middle lane
•Truck-Trailers: 87 km/h in the driving middle lane
•Buses: 98 km/h
Corinth-Athens Freeway, St.:57+550
Speed Limits (km/h):
120 for PCs, 80 for SU Trucks, 70 for Truck-Trailers, 90 for Buses
Transportation Research Board 3
2006 Annual Meeting

4. General Speed Limits:
The easy part
High speed
Vehicle Type FREEWAYS Other rural roads
roads
Passenger cars 130 110 90
Vehicle Type FREEWAYS
Buses 100 90 80
Articulated Buses 70 70 70 Freeways – wet pavement 110
School Buses 80 80 60 High speed roads – wet pavement 90
Trucks ≤ 3500 kgr 100 90 80 Other road network – wet pavement 80
Trucks > 3500 kgr 85 80 80 Freeways / High speed roads - Bridges 100
Semi Trailer Truck≤ 3500 kgr 80 80 70 Freeways / High speed roads - Tunnels 100
Semi Trailer Truck> 3500 kgr 80 70 70
Motorcyclists ≥ 125 cc 130 110 90
Motorcyclists < 125 cc 80 80 70

5. Local Speed Limits
The difficult part

6. King of the Road
It’s always the Driver!

7. By The Book
• Driver selects his/her safe speed accordingly
• Speed Limit is set only when driver can not perceive the
safe speed (obscured road, sudden pedestrian traffic,
pavement deterioration etc.)
• Speed Limit the last measure for road engineering
• CONDITIONAL and EXCUSED Speed Limit

8. Who Decides?
• Engineering Study
• Technical Team consisted by
– The Road Director,
– Local Police,
– Technical Chamber of Greece
• Primary Reference: OPERATING SPEED (V85)
• Use of Advisory Speed especially on Ramps for Heavy
Traffic
• Every 10 years regular reconsideration if not enforced by
accident history of specific site

9. Parameters?
• Grade (Speed Differential / Variance)
• Sharp curvature
• Sight Distance
• At-Grade Intersection (generally 70 km/h)
• Presence of Vulnerable road users (Children, Elderly People,
Bicyclists)
• Accident History
• Weaving Areas
• Roadside Development
• Specific Sites (Schools, Stadium, Animal Passage, etc)

10. For Example: Roadside
Development
Distance between Accesses (m)
MAXIMUM SPEED Rural & Urban
roads
LIMIT (KM/H) suburban (Throug
roads h roads)
70 350 -
60 300 -
50 ≤250 ≤250
≤50 ≤200 ≤200

11. For Example: Through Traffic
at Freeways
CROSS
Speed Limit
Roadway Functional Classification SECTION
(km/h)
TYPE
divided 130 120 110
Rural Freeways /High Speed Highways
undivided 100 90
Rural Roads between regions /counties divided 110 100
Rural Roads between cities/towns divided 100 90
Urban Freeway / Urban divided 90 80

12. For Example: Weaving Sections
at Interchanges
Speed
Weaving
Weaving Type Area Comments Limit
Length [m]
`
[km/h]
Rural Cloverleaf 100
200 & interchange
Urban type
180 80
Rural 100
250 &
between two
200 Urban 80
interchanges
180 Urban 60

13. For Example: Interchange
Ramps with max Cross-Slope 6%
Inner
Curve
Radius (m)
35 35 115 170 250 (340)
Speed
Limit
(km/h)
30 40 50 60 70 (80)

14. More Advisory Speeds
• Advice drivers on probable dangerous conditions when exceeding the
advisory speed limit like
• Intersections with restricted visibility
• Narrow Bridges or One-Lane Bridges
• Downgrades greater than 6%
• Ramps especially for Heavy Vehicles
• On Crest and Sag Vertical Curves
• It can be the operating speed or safe speed
• Accompanied with explaining sign

15. Conclusions
• A modern guide to help agencies set reliable speed limits that will be
obeyed
• Less necessity for enforcement
• Better acceptance by the driving population