Sensors + Intelligence + Enforcement = Compliance for Variable Speed Limit Signs
Gabino Travassos著
日期
2017年10月31日
Imagine you’re driving a road that you know is prone to accidents due to weather conditions or sudden congestion. 它可能是通往你山间小屋的一条蜿蜒的高速公路, 也可能是那条穿过城市的高速公路. 路上一直都有传感器来计算交通流量 monitor speeds, but now there are 公路上的传感器 detect rain, snow, temperature, loss of traction, low visibility, and wind. This is sent to a central server that digests this information and recommends a lower speed to the sign in advance of the condition. So, if there’s an icy patch in the fog around that corner, you should get a warning to reduce speed.
这就是情报所在. Information from the sensors is a non-stop fluctuating barrage of variables streamed to a database and interpreted by a program. 又冷又冰吗? 地面能见度低且下雪吗? 交通已经在减速了吗? 算法推荐的速度是多少? What is the fastest safe speed to drive in those conditions and what threshold needs to be reached to drop the speed and for how long? An algorithm could change the speed every 1/1000th of a second to any number above 0 and below the posted speed limit, 但是，尽管这可能是准确的，但它并不实用.
聪明的人可以在这个时候介入. A traffic engineer can set thresholds and buffer times and filters so the progression of the signs makes sense, 例如，它每60秒只能递减10, and if it steps down more than 30 it has to step down the previous sign to smooth out the speed. Or the signs could make recommendations and a human operator would have to approve the speed change. There would be a trained operator at the controls verifying road conditions on available cameras and making speed adjustments as necessary.
然后是 执行. Some Variable Speed Limit (VSL) systems have failed because the laws were not in place to enforce variable speed signs. A driver could refute the speed and demand proof that the sign had changed when the police were down the road and unable to verify it themselves visually. A database reporting system makes it possible to give tickets that will stand up in court; at precisely this minute the road conditions or the traffic congestion were X, 符号变成了 X at X 9点钟，司机正在旅行 X at X 点. It’s all in the database and it’s all viewable online for everyone: the police, 法官, 司机呢?. 没有这个安全的验证过程, there can be no 执行 and therefore less compliance– and little benefit to the drivers.
在城市环境中，VSL标志也被逐车道部署, where the signs might include a red x indicating construction or obstacles in the lane ahead. In busy city highways the goal of the city is to reduce collisions, 系统在这方面很有效. An added benefit is drivers can see how speeds tend to not reduce in High Occupancy Vehicle lanes, 也许这将改变未来司机的行为.
“基于收集到的数据, it is observed drivers are reducing their speeds on variable speed corridors when a lowered speed limit is posted,Jennifer Locke(项目经理)说, 卑诗省交通及基建) 加拿大运输协会
IBI has experienced consultants who understand traffic engineering, 旅游资讯服务, 数据仓库, 数据可视化, 传感器部署, 智能城市, 及其策略. Our deployment of three VSL corridors in BC has won four recent engineering and road safety awards. AG平台密切合作 with the BC Ministry of 运输 and Infrastructure to design the software that manages these (and future) VSL corridors.
