This would be a case of substitution (vs. conversion) where in new rational metric size is used for the value of the measurement for the item being converted. While conversion maintains the original standard value (rounded appropriately for accuracy and precision), substitution defines a new standard value for the measurement. Substitution should not be confused with rounding.
Substituting new rational speed limits would be appropriate although some sign distances may have to be conversions since the sign location for larger overhead signs would be costly to change. Sometimes distances are not very accurate on signs anyhow since the placement of a sign is not always easily located by the distance so indicated based on constraints such as steep slopes, bridges, other signs etc. For more information on Substitution vs. conversion refer to Annex B.7 Conversion versus substitution Transitioning from traditional inch-pound units to American National Standard for Metric Practice (SI 10) April 2011. Howard R. Ressel Project Design Engineer New York State Department of Transportation From: owner-u...@colostate.edu [mailto:owner-u...@colostate.edu] On Behalf Of Mike Giron Sent: Sunday, July 05, 2015 7:58 PM To: U.S. Metric Association Subject: [USMA:54778] Re: International Coverage in Metric Off topic but I've often wondered, when we finally complete the transition to the metric system how will speed limits and distances be labeled? Will the be rounded? For instance 35 mph would be 60 km/h but 40 mph would also be 60 km/h, 15 mph would be 20 km/h? Distances, 1 mile is 1.6 km but would this be rounded up to 2 km? Will distances be rounded up or down as needed or will decimals be in place? I.E.: 1/4 mi 400 m, 1/2 mi 800 m, 3/4 mi 1.2 km or will it be 1 km? I've attached a visual I made so you get the idea[https://files.acompli.net/attach?iid=(null)&aid=0ca499ab-0a26-4dd2-90ad-7b1c8286632e&account_id=3] . Sent from Outlook<http://taps.io/outlookmobile> On Sun, Jul 5, 2015 at 4:48 PM -0700, "Peter Goodyear" <p...@alphalink.com.au<mailto:p...@alphalink.com.au>> wrote:
