Tunnel

Category

General Information, Transportation, Transport Facilities, Safety, Road Signs, Highway Signs, Traffic Signs

Message / Function

To indicate the location or the presence of a tunnel

	Source	Description
	UN 1968	Front view of arc tunnel portal with old style stonemasonry and four edges at top
	STVO A	Front view of arc tunnel portal with old style stonemasonry and four edges at top
	Chile	Front view of arc tunnel portal with old style stonemasonry
	Tern	Front view of arc tunnel portal with old style stonemasonry
	STVO D	Front view of arc tunnel portal with old style stonemasonry
	W-RSN	Front view of arc tunnel portal with old style stonemasonry and four edges at top
	STA	Front view of arc tunnel portal with five segments, horizontal line at bottom
	MUTCD	Front view of arc tunnel portal with old style stonemasonry and four edges at top, end of tunnel indicated
	U.S. National Park Service	Front view of arc tunnel portal, center line and end of tunnel indicated
	Québec	Perspective view of arc tunnel portal with old style stonemasonry, road with center line and end of tunnel indicated
	CNIS	Perspective view of arc tunnel portal, road and end of tunnel indicated
	SVI	Perspective view of arc tunnel portal, road and end of tunnel indicated
	Tern	Perspective view of arc tunnel portal, road with center line and end of tunnel indicated
	PMP RI	Perspective view of arc tunnel portal with old style stonemasonry, road with center line and end of tunnel indicated
	Argentina MSV	Front view of arc tunnel portal, horizontal line at bottom, rear view of car inside
	Testdesign Egger	Silhouette of tunnel, rear view of car inside
	Testdesign Egger	Silhouette of tunnel
	Kapitzki	Black square with arc tunnel indicated by white space
	Peru D	Horizontal line with narrow tunnel above

Discussion

While many pictograms used to indicate the location or the presence of a tunnel were derived from the example shown in the UN Convention on Road Signs and Signals, labeled UN 1968 above, displaying a front view of an arc tunnel portal with old style stonemasonry, some rely on presenting a perspective view of a tunnel with tunnel portal and end of the tunnel indicated some way, and a few even displaying the road with a center line, too. General use for all kinds of applications - especially when intended just for pedestrians - would be debatable concerning versions with center line.

In our research we found only very limited information on data from tests, as all studies covered just the message Tunnel ahead is closed:

In a project concerning the comprehensibility of graphical symbols used on highways using a Comprehensibility Judgment Test (identical with the Comprehensibility Estimation procedure), eleven pictograms were examined in four countries regarding their suitability to convey the message Tunnel ahead is closed (Brugger, 2006). Images with a perspective view of a tunnel were judged as better understandable than simple tunnel portals, especially when also the road with a center line was explicitly displayed, as shown in the pictogram labeled Tern above. Only in Spain the UN 1968 variant was judged best. Generally portals shown as an arc were seen as better comprehensible than the portals with four edges at the top.

The tunnel was identified correctly by more than 80 % of the respondents in each of the variants examined in the following Comprehension Test (Siebenhandl et.al., 2006). Only persons holding a driving license participated in this research that was focused on Variable Message Signs (VMS) for traffic environments.

Recommendations

Regarding the research available we recommend the use of a symbol like TS2310 Tunnel from the Tern symbol set, which was designed on basis of the tests mentioned above.

Furthermore we advocate to conduct a study including a Comprehension Test comparing several concepts shown above to determine the image content working best. Relevant context information should be provided to the respondents of that project. Detailed information about the most frequent responses given in each of the response categories must be supplied for each pictogram variant tested to correctly judge comprehensibility and improve designs, if necessary.

Tests of pictograms of referent Tunnel / Tunnel ahead is closed

Brugger Ch. (2006): Comprehensibility Judgment Test. Report In-Safety, Contract No 506716.

Siebenhandl, K., Brugger, Ch., Simlinger, P., Egger, S., Hollo, P., Weinberger, J., Vasek, J. (2007): Results of the Comprehension Tests on pictograms conducted in Austria, the Czech Republic and Hungary; Report In-Safety, 506716.