![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 interchanges 80
180 Urban 60](https://image.slidesharecdn.com/speedlimitsrss2007psarianosetal-130327071549-phpapp02/85/Speed-limits-rss2007-psarianos-et-al-12-320.jpg)
Speed limits rss2007 psarianos et al
- 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 (Through roads 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 interchanges 80 180 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