In this article, Civil Engineer Thomas Lyden provides an overview of pavement markings in construction work zones. His discussion includes the importance of providing positive guidance within construction work zones, relevant standards, and typical methods of placing and removing markings.
Pavement Marking Removal & Construction Work Zones
Highway construction work zones place extraordinary demands on motorists. These work zones often require traffic to be routed to new travel paths through temporary lane shifts or detours. Shifting traffic from the original travel path to a new travel path requires the removal of existing or temporary pavement markings in order to successfully guide traffic through the work zone.
Motorists must receive positive guidance, through the use of signage and pavement markings, to successfully navigate these lane shifts. The objective of the pavement marking removal is to obliterate the old markings without scarring the pavement. If pavement markings are not completely obliterated, trace marking material may remain and confuse or mislead motorists to the original travel path rather than the new intended path. Removal methods that scar the pavement surface might, under certain weather or light conditions, suggest the original travel path remains the intended path. These scars, or “ghost markings,” are a recognized hazard in the industry.
STANDARDS RELEVANT TO PAVEMENT MARKING REMOVAL
Many states have construction specifications and standards specifying the percentage of marking material removed, depth of pavement scarring permitted, or both. Typically these specifications strike a balance between completely removing the marking and minimizing the damage to the pavement.
The Manual on Uniform Traffic Control Devices (MUTCD) requires that “Markings that are no longer applicable for roadway conditions or restrictions and that might cause confusion for the road user shall be removed or obliterated to be unidentifiable as a marking as soon as practical.” Elsewhere it states: “Pavement marking obliteration shall remove the non-applicable pavement marking material, and the obliteration method shall minimize pavement scarring. Painting over existing pavement markings with black paint or spraying with asphalt shall not be accepted as a substitute for removal or obliteration.”
It is important that the work product is inspected by both the contractor and agency inspectors under various lighting and weather conditions, to ensure the work meets specifications and to minimize confusion that motorists may experience by any remaining marking material or scarred pavement surface. This requires the work zone to be inspected under both day and night conditions, dry and wet conditions, and at various times of the day. The angle of the sun and direction of travel can have a significant impact on whether a scarred pavement is perceived as a pavement marking.
METHODS OF PAVEMENT MARKING REMOVAL
The work zone contractor is typically responsible for removing the old markings and applying the new, or temporary, markings. Many methods of pavement marking removal are available including grinding, various forms of blasting, burning, or chemical removal.
- Grinding is one of the most common, quickest, and cost-effective methods. The biggest disadvantage to grinding is scarring, affecting both the pavement texture and color.
- Water blasting does a good job of removing the markings without seriously damaging the pavement but is much slower and more expensive than grinding.
- Burning vaporizes pavement markings; however, the pavement surface may be burned leaving scars and hot marks.
- Chemical removal can be effective on both asphalt and concrete pavements but requires time for the chemical application to set before returning for power-washing.
COVERING PAVEMENT MARKINGS
Covering the old markings is an option through the use of black thermoplastic pavement markings or black-out tape. Black-out tape can move or slide under the pressure of traffic and if left in place too long, may become permanently affixed to the pavement.
The type of pavement, asphalt or concrete, plays a role in the contractor’s chosen method of removal and quality of results. The type and thickness of the original marking material to be removed, whether it is paint, thermoplastic, or epoxy impacts the speed at which the material can be removed and the cost-effectiveness of the chosen method. No one method is always better than another, and the operator’s skills and experience play a significant role in the quality of results.
Highway Engineering Investigations
The highway experts at Robson Forensic examine crash sites, use field measurements, scrutinize crash scene photos, and review infrastructure design documents to determine if highway factors or road conditions contributed to the cause of motor vehicle crashes.
For more information contact the author of this article or submit an inquiry.
Civil Engineer & Highway Engineering Expert
Thomas Lyden is a civil engineer with an impressive background covering the entire lifecycle of highway infrastructure. Prior to joining Robson Forensic, he was employed for 31 years by the Ohio Department of Transportation. Throughout his tenure as an ODOT employee, Thomas held various positions involving traffic engineering, maintenance operations, transportation planning, and project management. In his later roles with the Department of Transportation, Thomas established the training programs for winter roadway management, developed maintenance standards and oversaw routine maintenance activities involving pavement condition, guardrails, signs, pavement markings, and pavement drop-offs. Thomas is licensed as a Professional Engineer in multiple states.