Evaluating the Clarity of Highway Entrance-Ramp Directional Signs

Abstract

Near the approaches of interstate and other major highways, posted directional signs warn drivers about the proper lanes for entering these high-speed limited-access roadways. These signs are intended to guide drivers with clear, concise directions, but they may instead expose drivers to ambiguous information. This ambiguity has the potential for causing accidents when the wrong lane is chosen and the driver must cross several lanes of traffic in these frequently busy interchanges. The present study exantined the effectiveness of currently used interstate entrance-ramp directional signs) as well as a set of systematically manipulated alternative signs. Participants examined 94 sets of signs having various forms of simple vs. complex arrows and text (both alone and together) and for each, they were to indicatethe appropriate lanes and direction to enter the interstate highway. Participants also rated the same signs according to clarity. Results indicated that text alone and text plus arrow signs consistently produced better performance and higher clarity ratings compared to signs containing arrows alone. No differences were found in the set of text statements investigated. However, differences were found for the arrow alternatives. Simple arrows (both alone and with text) produced better performance and higher clarity ratings compared to complex arrows. The data show that the current highway signs are ambiguous, and that there are alternative designs that are clearer. In real-world applications, improved signs may reduceaccidentrates by decreasing decision errors.

Perceived Effectiveness of ‘No Turn on Red’ Traffic Signs

“…Past research and theory indicates that the use of both text and pictures improves comprehension (Pavio, 1971). Improved comprehension of complete text and symbol coding extends to traffic signage (Barnes, Levine, and Wogalter, 2000). Previous research indicates that partial combinations of symbol and text may impede message comprehension (Morrow, Hier, Menard, & Leirer, 1998).…”

Response Time and Decision Accuracy for ‘No Turn on Red’ Signs

“…Barnes, Levine and Wogalter (2000) examined interstate highway entrance-ramp direction signs. They found that two signs, one with an Arrow & Text, and one with Text-Only, were understood better than conventional Arrow-Only directional signs.…”

“…In examining the appropriate components of signs, several studies (Dewar, Ellis & Mundy, 1976;Kline, Buck, Sell, Bolan & Dewar, 1999;Kline, Ghali, Kline & Brown, 1990) have reported faster response times for signs with graphics (Symbols & Arrows), but a few studies report faster response times for Text-Only signs (Dewar, Ells, & Mundy, 1976;Shoptaugh & Whitker, 1984). Barnes, Levine and Wogalter (2000) examined interstate highway entrance-ramp direction signs. They found that two signs, one with an Arrow & Text, and one with Text-Only, were understood better than conventional Arrow-Only directional signs.…”