On-Pavement Signing

On-pavement signing shows a curve sign or other pavement marking symbol (such as the speed limit) in advance of a curve or other problem location.

Use of wording or signing on the pavement surface is more dramatic than vertical signing, which can get lost in the clutter of a streetscape. However, on-pavement signing has not been widely used in Iowa to address lane departures.

One study evaluated the use of on-pavement signing consisting of the word SLOW with a curve arrow framed between two horizontal bars. The treatment was applied along two curves. Both mean and 85th percentile speeds were reduced by around 1 mph (Hallmark et al. 2012).

No information is available about the crash impacts of on-pavement marking legends.

More information is provided in this technical brief, which summarizes information about pavement marking legends relevant to Iowa.


Hallmark, Shauna, Neal Hawkins, and Omar Smadi. Evaluation of Low-Cost Treatments on Rural Two-Lane Curves. Center for Transportation Research and Education, Iowa State University, 2012.

Image: SLOW and curve arrow between two horizontal bars on Des Moines County Road 99 pavement in advance of curve

On-pavement curve signing on Des Moines CR 99 (Shauna Hallmark et al./Institute for Transportation)

Image: On-pavement 25 mph speed limit signing on E-18 in Roland, Iowa

On-pavement speed limit signing on E-18 in Roland, Iowa (Shauna Hallmark et al./Institute for Transportation)

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