Share The Road Sign
<p>Does the following <a href="https://www.roadtrafficsigns.com/signs/motor-vehicle-bike-share-the-road-sign/sku-k-9081" rel="nofollow noreferrer">sign</a> mean that bikers and motor vehicle owners are sharing the same lane? But I thought it's not a good idea to share a lane. Thank you!</p>
<p><a href="https://i.stack.imgur.com/XZK82.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/XZK82.png" alt="enter image description here" /></a></p>

<p>You did not state a jurisdiction, but this sign is of the style specified by the <a href="https://mutcd.fhwa.dot.gov/kno_2009r1r2r3.htm" rel="nofollow noreferrer">Manual on Uniform Traffic Control Devices (MUTCD)</a> which is used throughout the United States, so I will assume a jurisdiction which follows the MUTCD.</p>
<p>The &quot;Share the Road&quot; sign is numbered <a href="https://mutcd.fhwa.dot.gov/htm/2009r1r2r3/part2/part2c.htm#section2C60" rel="nofollow noreferrer">W16-1P</a>.  (The MUTCD version just has the words and not the car/bike symbols; the latter might be a recent update or a local variation.)  Its description reads:</p>
<blockquote>
<p>In situations where there is a need to warn drivers to watch for other slower forms of transportation traveling along the highway, such as bicycles, golf carts, horse-drawn vehicles, or farm machinery, a SHARE THE ROAD (W16-1P) plaque (see Figure 2C-12) may be used.</p>
</blockquote>
<p>So, as is generally the case for yellow <em>warning</em> signs, it does not have any effect on the laws which apply.  (It is generally only white <em>regulatory</em> signs that do that.)</p>
<p>Whether or not it is a &quot;good idea&quot; to share a lane, it is legal.  Both cars and bikes are entitled to use the road, and if it's a road with only one lane in this direction of travel, then necessarily they must share it.  Of course, they wouldn't typically travel side by side indefinitely, but they will be abreast briefly when a car passes a bike.  California law, as an example, requires only that <a href="https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&amp;sectionNum=21760." rel="nofollow noreferrer">the car stay at least three feet away from the bicycle</a> as it passes, when possible.</p>

traffic