opinions, findings, and conclusions expressed in this

Transcription

1 R. Blackwell Steve Technician Traffic opinions, findings, and conclusions expressed in this ( are those of author and not necessarily those of report Highway $ Transportation Research Council Virginia Cooperative Organization Sponsored Jointly by Virginia (A of Highways & Transportation and Department University of Virginia) July 1979 FINAL REPORT EVALUATION OF TREATED WOODEN SIGN POSTS by sponsoring agencies.) Charlottesville, Virginia VHTRC 8-R7

2 MR. W C N LSON, JR., Asst,raffic & Safety Engineer, _ VDH& TRAFFIC RESEARCH ADVISORY COMMITTEE MR. D. B. HOPE, Chairman, District Engineer, VDH&T MR. R. G. CORDER, Transp. Coordination Engineer, VDH&T HR. L. H. DAWSON, JR., Asst. Traffic & Safety Engineer, VDH&T MR. J. E. GALLOWAY, JR. Asst. Materials Engineer, VDHST DR. JAMIE HURLEY/,. Assistant Professor of Civil Engineering, VP! & SU MR. C.. LEIGH, Maintenance Engineer, VDH&T MR. R. F. MCCARTY, Safety Coordinator, FHWA MR. J. P. MILLS, JR., Traffic & Safety Engineer, VDH&T MR. R. L. PERRY, Asst. Transnortation nlanning Engineer, VDH&, MR. B. C. PIERCE, District Traffic Engineer, VDH&T MR. R. N. ROBERTSON, Research Engineer, VH&TRC MR. Fo D. SHEPARD, Research Engineer, VH&TRC ±i

3 view of Virginia Department of Highways and Trans- In need to conserve dwindling revenues, Traffic portation's Advisory Committee recommended that feasibility of Research unpainted, treated wooden sign posts instead of painted using be investigated. With subsequent change to use of posts treated wooden sign posts, Advisory Committee unpainted, that evaluation be extended to compare tar- recommended values of painted and unpainted posts. In evaluation, get attention was focused on residues formed from chemicals special to treat post and adverse effects y might have on used legibility and general appearance of sign panel. values of a painted and an unpainted post were observed target 36 months, retroreflective characteristics of After sign panel mounted on unpinted, treated wooden sign post not changed abnormally or significantly. Also had no on sign panel or twisting of sign post was streaking A comparison of target values of posts showed noted. painted post to be more visible at times; difference was SUMMARY under different conditions. and can be made inconsequential by using reflectors on minimal posts Department's decision to use unpainted, treated wooden sign posts was reconfirmed by results of evaluation. iii

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5 R. Blackwell Steve Technician Traffic Virginia Department of Highways and Transportation used wooden sign posts until recently when increasingly painted Committee also requested that target values of painted unpainted posts be evaluated. and objectives of this study were to investigate (i) any effects of unpainted, treated wooden sign posts on adverse qualities and general appearance of facing retroreflective on highway signs, and (2) comparative target values materials r,a,,ti,9.n,of,,t.es,.t., Post_ an,d. Sign PrePa, test sign was constructed using a seven-foot (2.13 m) One wooden sign post and a sign panel 12 inches (3.48 cm) treated by 18 inches (45.72 cm) high mounted one foot (3.48 cm) wide test sign was placed in lot of Charlottesville Office for exposure to wearing on December 29, Residency sign panel was installed facingsouth and was mounted on a stand in standard vertical position. test FINAL REPORT EVALUATION OF TREATED WOODEN SIGN POSTS by INTRODUCTION need to conserve revenues prompted a recommendation by pressing Traffic Research Advisory Committee that feasibility of unpainted, treated wooden sign posts be investigated. using initial use of unpainted, tmeated wooden sign posts, After PURPOSE AND SCOPE of painted and unpainted posts. EVALUATION OF THE SIGN FACING MATERIAL M e t h odpl gy top of post as shown in Figure i.. sign panel from fabricated from green, enclosed lens, reflective sheeting. was

6 12" mezer i inch!. Sign panel and post dimen- Figure for :he. eva!uarion sions o; he s{gn fa ing mat=ria!

7 evaluation consisted of making measurements of of sign material and obsemvazions of its me morefleczivity appearance. mezromefleczivi y of sign panel is general indication of percentage of light ir reflects, and if an esidue from chemicals used to treat post were to any on sign panel, rezromef!ec ive meadings would be co!!ecz expected to decrease. retroreflective readings Bimonthly taken at our were. n test sample (see Figure 2), A template locations used was ensure that all bimonthly readings were taken at same to on sign panel, A modified Gardner portable ref!ec- locations general appearance of sign panel was documented viaua! observationa,.which were recorded every two months also. by i in. 2.5a cm Figure 2. ReZroref ective reading!ocat'cns, Evaluation tometer was used to take readings,

8 average retroreflectivities (average of one reading each four locations) at beginning of study and after from months, along with difference of averages and per- 36 loss in retroreflectivity, are shown in Table i. centage Summary of Retroreflective Readings of Sign on Unpainted Post in retroreflectivity by 8%, which is considered normal; decreased sign panel was not affected by unpainted, refore, wooden sign post. Since greatest expected error for treated reflectometer is I, difference of averages of 1.12 is observations of treated wooden sign post and Visual showed no streaking of sign panel by residue from panel used to treat post. Also, no twisting of post chemicals During last three months of wearing, light occurred. m) above pavement level, two 2-ft. (.61 m.) by 2-fto (.61 m) (2.18 signs mounted 2 in. (5.8 cm) from top of posts, and STOP reflectors 3 in. (7.62 cm) by 8 in. (2.32 cm) fabricated two silver, enclosed lens, reflective sheeting mounted i ft. from cm) from bottom of signs were installed as shown (3.48 Figure 3. One of sign posts was painted with two coats in Department's white latex paint while or was left of Both were installed on a test site on Route 116 unpainted. Table i Average Difference of Averages Average % Loss can be noted from Table i, sign panel mounted on As treated wooden post during three years of outdoor wearing not significant. brown colored spots appeared on all four sides of post. EVALUATION OF TARGET VALUES Methodo'logy of..test_ Pos.ts_ and.signs P eparation test signs using treated wooden sign posts 7-ft. 2-in. Two south of Charlottesville.

9 3. Sign panel and post dimensions for Figure of traget value. evaluation meter 348 centimeters 2.54 I foot i inch

10 determine any differences in target values painted To unpainted treated wooden posts with STOP signs were evaluated and clear wear, day and night, and with sign faces perpen- in to lane of travel, sign backs perpendicular to dicular lane of travel, sign faces parallel to lane of travel reflectors perpendicular to lane of travel, and with sign with parallel to lane of travel without reflectors perpendic- faces to lane of travel. ular observations and photographs of four conditions Visual made day and night at different distances. posts were were at 1-ft. (3.48 m) intervals from I ft. (3.48 m) to examined ft. (152.4 m) and n at 7 ft. ( m) and 75 ft. 5 m) in daytime; and at i ft. (3.48 m), 2 ft. (6.96 m), (228.6 ft. ( m), and 7 ft. ( m) at night. 4 was found that during day, both posts were visible It all distances from which y were evaluated. night- at observations showed a little difference in results. At time from a distance of i ft. (3.48 m) and with headlights night, low and high beams, posts could be seen under all four on At 7 ft. ( m) with low-and igh-beam head- conditions. comparative visibilities shown in Table 2 were found. lights, can be seen from this table, at a distance of 7 ft. ( m) As night with low-beam.headlights., reflectors did delineate at and unpainted posts when sign faces painted parallel to were lane of travel and reflectors perpendicular to lane travel. With high-beam lights and same conditions, of post was more visible, while only reflector painted seen was unpainted post when sign faces were parallel to for lane of travel and reflectors perpendicular to lane travel. of Evaluation Results

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12 of a test sign on an unpainted wooden post Observations 36 months of exposure to wearing reconfirmed during Department':s decision to use unpainted, treated wooden sign posts. it is desirable to enhance visibility of unpainted If at night, reflectors will serve this purpose. post author greatly appreciates interest and guidance of N. Robertson, assistant head, and F. D. Shepard and M. R. Parker, R. engineers, of Virginia Highway and Transportation research Council. Also, acknowledgment is m de of support Research CONCLUSIONS ACKNOWLEDGMENTS given by John Shelor, traffic technician supervisor.