Page 1 f 6 RECOMMENDED PRACTICES PART SECTION SUB-SECTION General Pavement markings prvide mtrists with valuable guidance and radway infrmatin. Pavement markings have specific functins; they guide the mvement f traffic and prmte safety n the highway. In sme cases they are used t supplement the messages f ther traffic cntrl devices. Fr many years, Alberta Transprtatin has mainly used cnventinal paint lines fr highway markings. This type f marking quickly begins t wear as sn as the highway is pen t traffic and generally requires painting within ne year, depending n traffic vlumes. Guidance prvided by cnventinal paint markings may be belw recmmended retr-reflectivity levels fr many mnths f the year. Pavement markings play a critical rle in radway safety and driver cmfrt. Durable pavement markings last much lnger than cnventinal traffic paint markings (slvent r water based paints) befre needing replacement. Durable pavement markings are divided int the fllwing categries: Premium traffic paint; Traffic marking tape; Wet Night High Visibility traffic marking tape; Nn-prfiled durable plastic markings; Wet Night High Visibility durable plastic marking; and Snwplwable raised pavement markers. Durability f the marking is judged by the lasting pwer f the marking material. It is mst ften based n a physical measure, such as the percentage f the marking material remaining and the annual retrreflectivity f the marking. Durable markings can be surface applied r inlayed (recessing f pavement marking flush r slightly belw pavement surface). It is imprtant t nte that when surface applying durable markings the service life is greatly reduced, the majr cause being snwplw damage. Wet Night High Visibility durable plastic markings and traffic marking tape can prvide highly visible pavement markings in varius weather cnditins thrughut the year due t their being prfiled. Nnspecialized durable plastic markings and traffic marking tapes are nn-prfiled. Installing durable pavement markings is estimated t reduce cllisin csts by 2.5% when cmpared t radways with cnventinal paint markings. The fllwing are recmmended practices fr the selectin and installatin f durable pavement markings fr lngitudinal marking applicatins n Alberta highways.
Page 2 f 6 Standard Several factrs need t be cnsidered when selecting a suitable material type fr pavement markings (cnventinal paint versus durable markings). Factrs t cnsider include: Traffic vlumes and traffic cmpsitin; Type f radway surface and cnditin; Cmplexity f traffic peratins; Cllisin experience; Presence f verhead lighting; Life-span f the radway; Prduct histry; and Cst f marking material; and Material durability/retr-reflectivity. All the abve factrs will either directly r indirectly affect the marking s visibility and durability, as well as applicatin technique. Cnsidering the safety benefits and ther advantages ver cnventinal paint markings, durable pavement markings ffer an excellent investment pprtunity when traffic vlumes are high enugh. Based n an ecnmic analysis, durable pavement markings shuld be cnsidered fr applicatin in the fllwing cases (als refer t Table 1): On fur-lane divided highways where the AADT exceeds 15,000 and the pavement cnditin is gd (remaining service life f at least 8 years); On rural tw-lane undivided highways where the AADT exceeds 5,000 and the pavement cnditin is gd (remaining service life f at least 8 years); On urban tw-lane undivided highways where the AADT exceeds 8,000 and the pavement cnditin is gd (remaining service life f at least 8 years); and At new traffic signal installatins where the pavement cnditin is gd (remaining service life f at least 8 years). Urban areas are cnsidered t be thse with substantial develpment adjacent t the highway, and typically have reduced speed limits and/r raised curbs. Sme sectins f highway within cmmunity crprate limits may nt be cnsidered urban. Where durable pavement markings are t be implemented, cnsideratin shuld be given t implementing durable markings fr all lngitudinal marking types n that sectin f highway (i.e., center lines, edge lines, lane lines) using the same marking material. The use f durable marking prducts fr transverse and intersectin markings shuld be evaluated n a site/prject specific basis. Prduct Selectin Once the decisin has been made that durable markings are t be used n a specific prject, an apprpriate durable marking type shuld be selected. Durable marking materials are listed n the Alberta Transprtatin Prducts List at the fllwing website, under the heading Pavement Markings: http://www.transprtatin.alberta.ca/cntent /dctype253/prductin/pavementmark INGS.pdf
Page 3 f 6 Marking Material Type PREMIUM TRAFFIC PAINT DURABLE PLASTIC MARKINGS Nn Prfiled Wet Night High Visibility TRAFFIC MARKING TAPE Nn Prfiled Wet Night High Visiibility TEMPORARY PAVEMENT MARKINGS SNOWPLOWABLE RAISED PAVEMENT MARKERS (cnsidered a wet night prduct) Pavement markings are listed under the fllwing three categries: 1. Prven prducts are markings that have prvided adequate perfrmance n department prjects, 2. Trial prducts have been used n trial prjects fr Alberta Transprtatin and are being mnitred fr acceptability. 3. Ptential prducts have nt yet been used n Alberta Transprtatin prjects. When installing durable pavement markings, prven prducts frm the Alberta Transprtatin Prducts List shuld be used. Hwever, fr trial applicatins, prducts classified as trial prducts r ptential prducts may be used. The use f trial r ptential prducts shuld be crdinated with Technical Standards Branch. The prduct selected fr use will depend n the radway envirnment, required service life and desired retr-reflectivity. The mst ecnmic alternative material chice shuld be determined thrugh a Life Cycle Cst Analysis cmputatin. Befre any life cycle cst cmparisns f materials can be made, the basic prject life must be established (8 year time perid is generally used). The fllwing prvides guidance n the bserved perfrmance f durable marking prducts available in each categry: Premium Traffic Paint HD-21A Is a mre durable waterbrne traffic paint that may be used in lwer traffic areas and may prvide 1 t 2 years f service life. (white): 350 Millicandelas (Mcd) t 400 Mcd (yellw): 150 t 250 Mcd Surface applied. Durable Plastic Marking System 300, System 400, System 600, IBIS Strip Cld Plastic are currently listed as prven prducts. These markings are nrmally surface applied and may prvide 2 t 4 years f service life n lwer vlume rads. Initial retr-reflectivity (white): 300 t 350 Mcd (yellw): 250 t 350 Mcd
Page 4 f 6 Traffic Marking Tape Stamark High Perfrmance Tape 380I ES and Premark Tape are currently listed as trial prducts. These markings are surface applied and may prvide 2 t 4 years f service life n lwer vlume rads. Initial retr-reflectivity (white): 400 t 500 Mcd (yellw): 300 t 400 Mcd Wet Night High Visibility Durable Plastic Marking Rainline and Pathfinder durable markings are currently listed as prven prducts. These markings are inlaid and may prvide 4 t 8 years f service life n higher vlume rads. Initial retr-reflectivity (white): 350 t 450 Mcd (yellw): 250 t 350 Mcd Wet Night High Visibility Traffic Marking Tape 3M Tape Series 380AW is currently listed as a trial prduct. This tape marking is inlaid and may prvide 4 t 8 years f service life n higher vlume rads. Initial retr-reflectivity (white): 500 Mcd t 600 Mcd (yellw): 300 t 400 Mcd Initial trial failed, experiencing debnding and peeling. Re-installatin is currently being evaluated. Snwplwable Raised Pavement Markers Avery Dennisn LifeLite Mdel 101LP, 3M NightLine and Stimsnite Mdel 98 are currently listed as trial prducts and shuld be advanced t Prven status in summer 2010. These markings are snwplwable raised pavement markings which may prvide 4 t 8 years f service life. Placement typically 27 m apart f straight sectins and 18 m apart n curves. In the department s recent experience, surface applied durable marking prducts d nt meet the department s retr-reflectivity perfrmance requirements fr the specified duratin. Fr this reasn, the inlaying f prducts where feasible is recmmended. Hwever, it shuld be nted that in lwer speed and lwer vlume areas inlaid prducts may be subject t mre dirt/grit build up which will impact marking visibility. When cnsidering an inlaid durable marking prduct, it is imprtant t understand that pavement degradatin (cracking, segregatin f aggregate) may be accelerated as a result. In particular, pavement jints and lder pavements may experience mre degradatin as they are weaker. The value f the marking (i.e. the life cycle cst and benefits) needs t cnsider the impact milling has n the rad surface when the durable marking is inlaid. Pavements need t be assessed t ensure the milled area will nt deterirate due t milling r fail prir t the life f the marking being realized. If markings are milled int pavement alng lngitudinal jints, prblems can be expected. The jint will typically need crack sealing, and the applicatin f crack seal will
Page 5 f 6 bliterate the durable marking. As well, the use f mre cstly durable markings can have an impact n surface patching in that markings are lst if verlaid. If the decisin is t defer the patching t maintain the marking, rad user ride quality suffers. Guidelines fr Placement Durable pavement markings shuld be installed using the prprietary installatin methd fr that prduct. Recessing (inlaying) f durable pavement markings belw r flush t the pavement surface will prtect the markings frm snwplwing peratins and enhance their lnger term perfrmance. Pavement marking cnfiguratins shall be applied in accrdance with the Highway Pavement Marking Guide. Perfrmance Requirements/Warranty Surface applied durable pavement markings must meet the minimum dry perfrmance level f 125 mcd/lux/m 2 fr white markings and 100 mcd/lux/m 2 fr yellw markings fr a perid f 24 mnths frm the date f installatin when expsed t nrmal radway cnditins, and must stay in place fr a perid f at least 24 mnths, regardless f average daily traffic. and must stay in place fr a perid f at least 48 mnths, regardless f average daily traffic. Over the curse f the warranty perid, the retr-reflectivity will be evaluated ver segments f 1 kilmetre r the length f the line (whichever is less). All retr-reflectivity measurements shall be made n a clean dry surface using a 30 m gemetry retrreflectmeter. Randm measurements shall be taken thrughut any 1 kilmetre sectin with results averaged in rder t determine any area t be repaired. The evaluatin f lss f line will be ver 100 metre segments. Fr the purpses f warranty, a cumulative 10% r greater lss f line due t nn-adhesin n any 100 metre segment f marking will cnstitute failure f the material n that segment. References t Standards Highway Pavement Marking Guide, 2 nd Editin, 2003 Alberta Transprtatin Prducts List Inlaid durable pavement markings must meet the minimum dry perfrmance level f 125 mcd/lux/m 2 fr white markings and 100 mcd/lux/m 2 fr yellw markings fr a perid f 48 mnths frm the date f installatin when expsed t nrmal radway cnditins,
Page 6 f 6 Table 1: Recmmended Applicatin Criteria fr Durable Pavement Markings Radway Envirnment Urban Rural Radway Crsssectin Divided Undivided Divided Undivided AADT < 15,000 >= 15,000 < 8,000 >= 8,000 < 15,000 >= 15,000 < 5,000 >= 5,000 Remaining Pavement Life Cnsider Durable Markings? Cntinuus Illuminatin Present? Cnside r Wet Night Prduct N Yes Yes Yes N Yes Yes Yes N Yes Yes Yes N Yes Yes N Nte: Urban radway envirnment is classified as having substantial adjacent develpment, and reduced speed limit. Raised curb may als be present.