Intelligent Transportation Systems (ITS) promise significant increases in throughput and reductions in trip delay. ITS makes extensive use of Connected and Autonomous Vehicles (CAV) frequently broadcasting location, speed, and intention information. However, with such extensive communication comes the risk to privacy. Preserving privacy while still exchanging vehicle state information has been recognized as an important problem.

Mix zones have emerged as a potentially effective way of protecting user privacy in ITS. CAVs are assigned pseudonyms to mask their identity; a mix zone is an area where CAVs can change their pseudonyms to resist being tracked.

In order to be effective, mix zone placement must take account of traffic flows. Also, since a mix zone can degrade throughput, mix zones must be used sparingly. Determining the number and placement of mix zones is a difficult dynamic optimization problem. This paper outlines the various approaches recently taken by researchers to deal with this problem.

智能交通系统 (ITS) 有望显着提高吞吐量并减少行程延误。 ITS 广泛使用联网自动驾驶车辆 (CAV)，频繁广播位置、速度和意图信息。然而，如此广泛的沟通也带来了隐私风险。在交换车辆状态信息的同时保护隐私已被认为是一个重要问题。

混合区已成为 ITS 中保护用户隐私的潜在有效方法。 CAV 被分配假名以掩盖其身份；混合区是 CAV 可以更改其假名以防止被跟踪的区域。

为了发挥作用，混合区的布局必须考虑交通流量。此外，由于混合区会降低吞吐量，因此必须谨慎使用混合区。确定混合区的数量和位置是一个困难的动态优化问题。本文概述了研究人员最近为解决这个问题而采取的各种方法。