OpenDRIVE 1.6

The following deliverables are provided for OpenDRIVE:

OpenDRIVE可交付以下内容：

The OpenDRIVE format provides a common base for describing road networks with Extensible Markup Language (XML) syntax, with the file extension xodr. The data that is stored in an OpenDRIVE file describes the geometry of roads as well as features along the roads that influence the logics, for example, lanes and signals. The road networks that are described in the OpenDRIVE file can either be synthetic or real. The main purpose of OpenDRIVE is to provide a road network description that can be fed into simulations and to make these road network descriptions exchangeable.

OpenDRIVE格式使用文件拓展名为xodr的可扩展标记语言（XML）作为描述路网的基础。存储在OpenDRIVE文件中的数据描述了道路的几何形状以及可影响路网逻辑的相关特征(features)，例如车道和标志。OpenDRIVE中描述的路网可以是人工生成或来自于真实世界的。OpenDRIVE的主要目的是提供可用于仿真的路网描述，并使这些路网描述之间可以进行交换。

The format is organized in nodes that can be extended with user defined data. This facilitates a high degree of specialization for individual applications (usually simulations) while maintaining the interoperability that is required for the exchange of data between different applications.

该格式将通过节点(nodes)而被构建，用户可通过自定义的数据扩展节点。这使得各类应用（通常为仿真）具有高度的针对性，同时还保证不同应用之间在交换数据时所需的互通性。

This specification uses a standard information structure. The following rules apply regarding normativity of sections:

本说明文档使用标准信息结构。以下规则适用于确认章节的规范性：

ASAM OpenDRIVE is part of the ASAM simulation standards that focus on simulation data for the automotive environment. Next to ASAM OpenDRIVE, ASAM Provides other standards for the simulation domain, like ASAM OpenSCENARIO and ASAM openCRG.

ASAM OpenDRIVE是ASAM仿真标准的一部分，该标准专注于车辆环境的仿真数据。除了ASAM OpenDRIVE，ASAM还提供其他仿真领域的标准，例如ASAM OpenSCENARIO和ASAM OpenCRG。

ASAM OpenDRIVE defines a storage format for the static description of road networks. In combination with ASAM OpenCRG it is possible to add very detailed road surface descriptions to the road network. ASAM OpenDRIVE and ASAM OpenCRG only contains static content. To add dynamic content ASAM OpenSCENARIO is needed. Combined all three standards provide a scenario-driven description of traffic simulation that contains static and dynamic content

ASAM OpenDRIVE为路网的静态描述定义了一种存储格式。通过与ASAM OpenCRG结合使用，可以将非常详细的路面描述添加至路网当中。OpenDRIVE和ASAM OpenCRG仅包含静态内容，若要添加动态内容，则需要使用ASAM OpenSCENARIO。三个标准的结合则提供包含静态和动态内容、由场景驱动的对交通模拟的描述。

OpenDRIVE 1.6 contains elements that were introduced in version 1.5 but are not compatible with version 1.4. To ensure compatibility with versions 1.4 and 1.5, these elements are technically defined as optional in the XML schema of version 1.6. They are marked as "Optional for backwards compatibility" in the annotations of the UML model.

OpenDRIVE 1.6版包含了在1.5版中出现过的元素，但这些元素与1.4版不兼容。为了确保能与1.4版和1.5版兼容，这些元素在1.6版的XML模式中从技术上被定义为可选。在UML模型的注释中，它们被标记为“向后兼容的可选”。

OpenDRIVE data is stored in XML files with the extension .xodr. Compressed OpenDRIVE files have the extension ".xodrz" (compression format: gzip).

OpenDRIVE数据存储于XML文件中，文件拓展名为.xodr。OpenDRIVE压缩文件的拓展名为".xodrz"（压缩格式gzip）。

The OpenDRIVE file structure conforms to XML rules; the associated schema file is referenced in the XML. The schema file for the OpenDRIVE® format can be retrieved from https://www.asam.net/standards/detail/opendrive/

OpenDRIVE文件的结构符合XML规则；关联的模式文件在XML中得到引用。用于OpenDRIVE®格式的模式文件可从以下链接中读取： https://www.asam.net/standards/detail/opendrive/

Elements are organized in levels. Elements with a level that is greater than zero (0) are children of the preceding level. Elements with a level of one (1) are called primary elements.

元素被置于层级中。层级大于零(0)的元素是上一层级的子级，层级等于一（1）的元素则为主元素。

Each element can be extended with user-defined data. This data is stored in so-called user data elements.

可通过用户定义的数据对每个元素进行拓展。此类数据被存储于“用户数据”元素中。

All floating-point numbers used in OpenDRIVE are IEEE 754 double precision floating-point numbers. In order to ensure accurate representation of floating-point numbers in the XML representation, implementations SHOULD use a known correct accuracy preserving minimal floating-point printing algorithm (e.g. [Burger96], [Adams18]), or ensure that 17 significand decimal digits are always produced (e.g. using the "%.17g" ISO C printf modifier). Importing implementations should use a known correct accuracy preserving floating-point reading algorithm (e.g. [Clinger90]).

所有在OpenDRIVE中使用的浮点数均为IEEE 754双精度浮点数。为了确保XML表示法中对浮点数的表示精准，应（should）使用已知的、保留最小的浮点数打印算法（比如[Burger96], [Adams18])的正确精度来进行执行，或者执行应该确保始终有17个有效十进制数字得到生成（例如使用the "%.17g" ISO C printf 修饰符）。在导入执行时，建议（should）使用一个已知的正确精度来保留浮点数并读取算法（例如 [Clinger90])。

[Burger96] Robert G. Burger and R. Kent Dybvig: "Printing floating-point numbers quickly and accurately." In proceedings of ACM SIGPLAN 1996 conference on Programming Language Design and Implementation, Philadelphia, PA, USA, May 1996, pp. 108-116

[Burger96] Robert G. Burger和R. Kent Dybvig：“快速、准确地打印浮点数”。引用于美国宾夕法尼亚州费城举行的ACM SIGPLAN 1996编程语言设计与执行会议第108-116页，1996年5月。

[Adams18] Ulf Adams: "Ryū: fast float-to-string conversion." ACM SIGPLAN Notices, Vol. 53, No. 4, April 2018, pp. 270-282

[Adams18] Ulf Adams：“Ryū：浮点数到字符串的快速转换。” 引用于ACM SIGPLAN报告的第53卷第4号第270-282页，出版于2018年4月。

[Clinger90] William D. Clinger: "How to Read Floating Point Numbers Accurately." ACM SIGPLAN Notices, Vol. 25, No. 6, June 1990, pp. 92-101

[Clinger90] William D. Clinger: "如何精确读取浮点数"。引用于ACM SIGPLAN报告的第25卷第6号第92-101页，出版于1999年6月。

Multiple files can be combined with an <include> tag at the appropriate locations. Upon parsing this tag, OpenDRIVE readers shall immediately start reading the file specified as attribute of the tag. It is the user’s responsibility to make sure that contents read from an include file are consistent with the context from which the inclusion starts.

可使用<include>标签在适当的位置对多个文件进行合并。解析该标签后，OpenDRIVE读取器须（shall）立刻开始读取作为标签属性的文件。用户有责任确保从包含文件中读取而来的内容与包含开始时的上下文一致。

The parent tag under which the <include> tag occurs must be present in both, the parent file and the included file.

<include>标签发生在父标签下，该父标签必须（must）存在于父文件以及包含文件内。

Example 示例:

Original File 原始文件

Included File 包含文件

All attributes that can be used in an OpenDRIVE file are fully annotated in the UML model:

所有可在OpenDRIVE文件中使用的属性都能在UML模型里得到完整标注：

Ancillary data should be described near the element it refers to. Ancillary data contains data that are not yet described in OpenDRIVE, or data that is needed by an application for a specific reason. Examples are different road textures.

应（should）在辅助数据所引用的元素附近对其进行描述。辅助数据包含OpenDRIVE中还未描述或出于特殊原因为某一应用所用的数据，如不同的道路纹理。

In OpenDRIVE, ancillary data is represented by <userData> elements. They may be stored at any element in OpenDRIVE.

在OpenDRIVE中，辅助数据用 <userData> 元素来表示。它们可（may）被存储在OpenDRIVE任意元素中。

OpenDRIVE allows including external files into the OpenDRIVE file. The processing of the files depends on the application.

OpenDRIVE允许将外部文件包含在OpenDRIVE文件中，而如何处理该类文件则视应用而定。

Included data is represented by <include> elements. They may be stored at any position in OpenDRIVE

包含数据用<include>元素来表示，可（may）被存储在OpenDRIVE里任意位置。

OpenDRIVE offers the possibility to integrate user generated layouts for elements like road marks or signals. The design of these alternative layouts is not stored in OpenDRIVE, but in the application.

可在OpenDRIVE中对用户生成的元素布局（如路标或标志）进行集成。这些附加的布局设计并不存储在OpenDRIVE中，而是存储在用户应用中。

In OpenDRIVE, different layout types are represented by <set> elements. They may be stored at any position in OpenDRIVE.

在OpenDRIVE中，不同布局类型用 <set> 元素来表示，其可（may）存储在OpenDRIVE里任意位置。

Every <set> element may be followed by one or more <instance> element that specifies the layout.

每个 <set> 元素之后都可以（may）关联一个或多个对布局进行说明的<instance>元素。

Raw data or data from external sources that is integrated in OpenDRIVE may be of varying quality. It is possible to describe quality and accuracy of external data in OpenDRIVE.

集成到OpenDRIVE的原始数据或来自外部资源的数据质量可能（may）参差不齐。外部数据的质量和准确性可以在OpenDRIVE中得到描述。

The description of the data quality is represented by <dataQuality> elements. They may be stored at any position in OpenDRIVE.

对数据质量的描述用 <dataQuality> 元素来表示。它们可（may）存储在OpenDRIVE中的任意位置。

Measurement data derived from external sources like GPS that is integrated in OpenDRIVE may be inaccurate. The error range, given in [m], may be listed in the application.

集成到OpenDRIVE、源自于GPS等外部资源的测量数据可能（may）存在误差。以[m]为单位的误差范围可（may）在应用中被列出。

The absolute or relative errors of road data are described by <error> elements within the <dataQuality> element.

道路数据的绝对或相对误差在<dataQuality>元素中用 <error> 元素来描述。

Some basic metadata containing information about raw data included in OpenDRIVE is described by the <rawData> element within the <dataQuality> element.

某些基本元数据涵盖了被包括在OpenDRIVE中的原始数据信息，这些原始数据在 <dataQuality> 元素中用 <rawData> 元素来描述。

OpenDRIVE uses three types of coordinate systems, as shown in the below figure:

OpenDRIVE使用三种类型的坐标系，如下图所示：

If not indicated otherwise, the local coordinate system is located and oriented relative to the reference line coordinate system. The reference line coordinate system is located and oriented relative to the inertial coordinate system by specifying the origin, as well as the heading, roll, and pitch rotation angles of the origins with respect to each other.

若无另外说明，对局部坐标系的查找与定位将相对于参考线坐标系来进行。对参考线坐标系位置与方向的设定则相对于惯性坐标系来开展，具体方法为对原点、原点的航向角/偏航角、横摆角/翻滚角和俯仰角的旋转角度及它们之间的关系进行详细说明。

The inertial system is a right-handed coordinate system according to ISO 8855 with the axes pointing to the following directions (see Figure 7):

根据ISO 8855惯性坐标系是右手坐标系，其轴的指向方向如下（见图7）：

For geographic reference, the following convention applies:

以下惯例适用于地理参考：

Elements like objects and signals can be placed within the inertial coordinate system by applying a heading, followed by pitch, followed by roll:

通过依次设置航向角/偏航角（heading）、俯仰角（pitch）和横摆角/翻滚角（roll），元素（如物体、标志等）可被置于惯性坐标系中：

Figure 7 shows the positive axes and positive directions of the corresponding angles.

图7展示了对应角的正轴与正方向。

x’/y’/(z’=z) denotes the coordinate system after rotating x/y/z with the heading angle around the z-axis. The coordinate system x’’/(y’’=y’)/z’’ denotes the coordinate system after rotating x’/y’/z’ with the pitch angle around the y’-axis. The final rotated coordinate system (x’’’=x’’)/y’’’/z’’’ is obtained after rotating system x’’/y’’/z’’ with roll angle.

x’/y’/(z’=z) 指的是以航向角/偏航角围绕z轴旋转x/y/z轴之后的坐标系。坐标系x’’/(y’’=y’)/z’’指的是以俯仰角围绕y’轴旋转x’/y’/z’轴之后的坐标系。最后，坐标系(x’’’=x’’)/y’’’/z’’’在用横摆角/翻滚角旋转x’’/y’’/z’’后获得。

The reference line coordinate system applies along the reference line of a road. It is a right-handed coordinate system. The s-direction follows the tangent of the reference line. It has to be noted that the reference line is always located within the x/y-plane defined by the inertial coordinate system. The t-direction is orthogonal to the s-direction. The right-hand system is completed by defining the up-direction h orthogonal to x-axis and y-axis. The following degrees of freedom are defined:

参考线坐标系同样也是右手坐标系，应用于道路参考线。s方向跟随着参考线的切线方向。这里需要说明的是：参考线总是被放置在由惯性坐标系定义的x/y平面里。t方向与s方向成正交。在定义完垂直于x轴和y轴、朝上的h方向后，整个右手坐标系才算完成。被定义的自由度如下：

Similar to the inertial system, the s’/t’/h’ and s’’’/t’’’/h’’’ denote the rotated systems around heading and roll angle. The reference line coordinate system can be positioned in the inertial space by providing the origin’s coordinates and the orientation (heading) of the origin with respect to the inertial system, as shown in figure 11.

与惯性系相似，s’/t’/h’ 与s’’’/t’’’/h’’’指的是围绕航向角/偏航角和横摆角/翻滚角旋转后得到的坐标系。如图11所示，通过提供原点坐标以及相对于惯性坐标系原点的方向（航向角/偏航角），参考线坐标系可（can）被置于惯性空间中。

Superelevation causes a roll in the reference line.

超高程导致参考线内产生横摆角/翻滚角。

For the s/t/h coordinate system no pitch is possible, the elevation of the reference line is as follows. Elevation has no effect on the length of s.

俯仰角在s/t/h轴坐标系中不可能出现，参考线的高程如下图所示。高程对s的长度不产生影响。

The local system is a right-handed coordinate system according to ISO 8855 with the axes pointing to the following directions. For a non-rotated coordinate system the following applies:

根据ISO 8855局部坐标系是右手坐标系，其轴的指向方向如下。以下内容适用于非旋转坐标系：

Elements like objects can be placed within the local coordinate system by applying a heading, followed by pitch, followed by roll:

可（can）通过依次设置航向角/偏航角、俯仰角和横摆角/翻滚角，将元素（例如物体）置于局部坐标系中：

Within the local system, the following angles are defined:

在局部坐标系中，以下角度得到定义：

Figure 14 shows the positive axes and positive directions of the corresponding angles. The local system can only be positioned in reference line space by providing the origin of the local coordinate system within the reference line system and the orientation (heading) of the local system with respect to the reference line system, as shown in figure 16.

图14展示了对应角的正轴与正方向。局部坐标系只能（can）通过以下方法被置于参考线空间中：如图16所示，在参考线坐标系中提供局部坐标系的原点和相对于参考线坐标系、局部系原点的方向（航向角/偏航角）。

Inertial, reference line and local system are used in OpenDRIVE at the same time. An example for positioning and orientation of the different coordinate systems relative to each other is depicted in Figure 17.

惯性坐标系、参考线坐标系和局部坐标系将在OpenDRIVE中同时被使用。图17中的示例描述了三个坐标系相对于彼此的位置与方向设定。

Spatial reference systems are standardized by the European Petroleum Survey Group Geodesy (EPSG) and are defined by parameters describing the geodetic datum. A geodetic datum is a coordinate reference system for a collection of positions that are relative to an ellipsoid model of the earth.

空间参考系的标准化由欧洲石油调查组织(EPSG)执行，该参考系由用于描述大地基准的参数来定义。大地基准是相对于地球的椭圆模型的位置合集所作的坐标参考系。

A geodetic datum is described by a projection string according to PROJ, that is, a format for the exchange of data between two coordinate systems. This data shall be marked as CDATA, because it may contain characters that interfere with the XML syntax of an element’s attribute.

通过使用基于PROJ（一种用于两个坐标系之间数据交换的格式）的投影字符串来完成对大地基准的描述。该数据应（shall）标为CDATA，因为其可能（may）包含会干预元素属性XML语义的字符。

In OpenDRIVE, the information about the geographic reference of an OpenDRIVE dataset is represented by the <geoReference> element within the <header> element. proj-strings, as shown in the below XML Example, contain all parameters that define the used spatial reference system:

在OpenDRIVE中，关于数据集的地理参考信息在<header>元素的<geoReference>元素中得以呈现。Proj字符串（如以下XML示例中所示）包含了所有定义已使用的空间参考系的参数：

For detailed information on proj-strings, see https://proj.org/usage/projections.html

关于proj字符串的细节信息，参见 https://proj.org/usage/projections.html

There shall be no more than one definition of the projection. If the definition is missing, a local Cartesian coordinate system is assumed.

投影的定义不能（shall）多于一个。若定义缺失，那么则假定为局部笛卡尔坐标系。

It is highly recommended to use official parameter sets for proj-strings, which can be found at https://epsg.io/. Parameters should not be changed. Some spatial reference systems, for example, UTM, have implicit false easting and northing, which are defined using the parameters +x_0 and +y_0.

这里强烈建议使用proj字符串的官方参数组（使用该链接查询字符串： https://epsg.io/ ）。参数不应（should）被改变。一些空间参考系如UTM具有隐东及北伪偏移，这里使用+x_0与+y_0参数对它们进行定义。

If you want to apply an offset, use the <offset> element instead of changing all parameter values.

若您想应用偏移，请使用<offset>元素，而不是改变所有参数值。

XML example XML示例:

Rules: 规则：

The basic element of every road in OpenDRIVE is the road reference line. All geometry elements that describe the road shape and further properties of the road are defined along the reference line. These properties include lanes and signals.

道路参考线是OpenDRIVE中每条道路的基本元素。所有描述道路形状以及其他属性的几何元素都依照参考线来定义，这些属性包括车道及标志。

By definition, the reference line runs in s-direction, while the lateral deviation of objects from the reference line runs in t-direction.

按照定义，参考线向s方向伸展，而物体出自参考线的侧向偏移，向t方向伸展。

Figure 20 shows the different parts of a road in OpenDRIVE.

图20展示了OpenDRIVE中一条道路的不同部分。

In OpenDRIVE, the geometry of a reference line is represented by the <geometry> element within the <planView> element.

在OpenDRIVE中，参考线的几何形状用<planView>元素里的 <geometry> 元素来表示。

The <planView> element is a mandatory element in every <road> element.

<planView> 元素是每个 <road> 元素里必须要用到的元素。

Attributes 属性

Rules 规则

The following rules apply to road reference lines:

以下规则适用于道路参考线：

Related topics 相关内容

A straight line, as shown in figure 22, is the simplest geometry element. It contains no further attributes.

如图22所示，直线是最简单的几何形状元素。它不包含其他属性。

In OpenDRIVE, a straight line is represented by a <line> element within the <geometry> element.

在OpenDRIVE中，直线用<geometry> 元素里的 <line> 元素来表示。

XML Example XML示例

Related topics 相关内容

A spiral is a clothoid that describes a changing curvature of the reference line, as shown in figure 23. Spirals may be used to describe the transition from a <line> to an <arc> without causing leaps in the curvature.

如图23所示，螺旋线是一条描述参考线变化曲率的回旋曲线。螺旋线可（may）被用来描述曲率在<line>到<arc>连贯的转换。

A spiral is characterized by the curvature at its start position (@curvStart) and the curvature at its end position (@curvEnd). Along the arc length of the spiral (see @length of the <geometry> element), the curvature is linear from the start to the end.

螺旋线是以起始位置的曲率(@curvStart)和结束位置的曲率(@curvEnd)为特征。沿着螺旋线的弧形长度（见 <geometry> 元素@length），曲率从头至尾呈线性。

It is also possible to arrange several <line>, <spiral>, and <arc> elements in a sequence in order to describe complex curvatures.

也可以按顺序排列 <line> 、 <spiral> 和 <arc> 几个元素，从而对复杂曲率进行描述。

In OpenDRIVE, a spiral is represented by a <spiral> element within the <geometry> element.

在OpenDRIVE中，螺旋线用<geometry> 元素里的<spiral>元素来表示。

Attributes 属性

XML Example XML示例

Rules 规则

The following rules apply to spirals:

以下规则适用于螺旋线：

Related topics 相关内容

An arc, as shown in figure 24, describes a road reference line with constant curvature.

如图24所示，弧线描述了有着恒定曲率的道路参考线。

In OpenDRIVE, a spiral is represented by a <arc> element within the <geometry> element.

在OpenDRIVE中，弧线用<geometry> 元素里的<arc>元素来表示。

Attributes 属性

XML Example XML示例

Rules 规则

The following rules apply to arcs:

以下规则适用于弧线：

Related topics 相关内容

The combination of all geometry elements available in OpenDRIVE allows for the creation of a great variety of road courses, as shown in figure 25.

如图25所示，通过对OpenDRIVE中所有可用的几何形状元素进行组合，便可以创建诸多种类的道路线。

To avoid leaps in the curvature, it is recommended to use spirals to combine lines with arcs and other elements with different curvatures.

为避免曲率中出现断口，建议使用螺旋线将直线与弧线以及其他有不同曲率的元素进行结合。

XML Example XML示例

See the sample file Ex_Line-Spiral-Arc.xodr

见示例文件Ex_Line-Spiral-Arc.xodr

Cubic polynoms may be used to generate complex road courses that are derived from measurement data. For a given sequence of measured coordinates along the reference line in the x/y-coordinate system, measurement pairs define the polynom limits of the segment.

三次多项式可（may）用来生成衍生于测量数据的复杂道路走向。测量对为x/y坐标系中沿参考线的被测量坐标的指定次序定义了线段的多项式极限。

The reference line of the road is described by a local cubic polynom. Specifying continuity conditions, for example segment continuity, tangent and/or curvature continuity, at the limits of the segment allows to merge several cubic polynom segments and to form a global cubic spline interpolation curve for the entire course of the road. As an additional advantage, routing along polynoms can be realized more efficiently than along clothoids.

局部三次多项式描述了道路的参考线。通过对线段极限处的连续性条件例如线段连续性、切线和/或曲率连续性等进行详细说明，可以对多个三次多项式线段进行融合并且为整个道路走向生成一条全局三次样条线插值曲线。另一个优点则是，沿着多项式的路径方式比沿回旋曲线更有效。

Parametric cubic curves are used for complex curves that are to be generated from measurement data. Parametric cubic curves are more flexible and allow a greater variety of road courses than cubic polynoms. In comparison to cubic polynoms that are defined in a x/y-coordinate system or as local u/v-coordinates, the coordinates x and y are interpolated separately by their own splines with respect to a common interpolation parameter p.

参数三次曲线被用于描述从测量数据中生成的复杂曲线。参数三次曲线相较于三次多项式更为灵活，它能描述更多种类的道路线。与在x/y坐标系中被定义或被当成局部u/v坐标系的三次多项式比起来，x坐标与y坐标的插值是通过它们自身的样条相对于共同的插值参数p而进行的。

Some properties of roads are described based on the cross section of the road. The road cross section is the orthogonal view of the road at a given point on the road reference line. An example of a property that refers to the road cross section is superelevation. Elements that are valid for a road cross section are valid for the whole width of the road at a given point on the reference line.

某些道路属性是基于道路横截面得到描述的，道路横截面是道路参考线上给定点处的道路正交视图。超高程是一种与道路横截面相关的属性。如果元素对道路横截面有效，那么它对道路参考线上给定点处的整个宽度都有效。

Other road properties are described based on the plan view of the road. This includes lanes and road elevation. For these properties, the term road section is used. Road sections describe parts of roads and their specific properties along the s-coordinate of the road reference line. Properties that are valid for a road section may not be valid for the whole width of the road, but for specific lanes only.

其他道路属性是基于道路平面图得到描述的，其中包括车道和道路高程。这些属性称为道路段，其描述了道路的各个部分以及它们沿道路参考线s坐标的特定属性。对路段有效的属性仅对特定车道有效，可能（may）对整个道路宽度无效。

That means it is possible to create sections for different properties like road type or lane sections. Sections are created by an additional element within the <road> element, using new start s-coordinates. The length of a section is implicitly given by the difference between two given s-start positions. Sections shall be stored in ascending order of s-coordinates.

这意味着可为不同属性（例如道路类型或车道段）创建不同的道路段，方式是使用新的起始s坐标以及 <road> 元素中的附加元素。两个给定s-起始位置之间的差别隐式地指定了组的长度。段的存储必须（shall）按s坐标升序来进行。

For applications to navigate through a road network, roads must be linked to each other. Roads may be connected to another road or a junction. Isolated roads are not connected to other roads or junctions.

为了能够在路网中行进，道路必须（must）相互连接。道路可以（may）连接到其他道路或交叉口上（孤立的道路除外）。

Figure 35 shows scenarios of prohibited, allowed, and recommended road linkage. It is important that the lanes and reference lines of the roads to be linked have a direct linkage to its predecessor or successor. Overlaps or leaps should be avoided but are not prohibited if the reference lines are connected properly.

图35的场景展示了禁止、允许以及建议的道路连接方式。非常重要的是，相互连接的道路的车道及其参考线需与其前驱以及后继道路的车道及其参考线直接连接。如果参考线连接正确，则应该避免重叠或断口，但不完全禁止。

Figure 36 shows the allowed scenarios for road linkage outside junctions, with two roads running in the same, opposite, or converging directions. Road linkage is not possible, if the two reference lines are not connected to each other.

图36的场景展示了在交叉口外可行的道路连接方式，其中包括两条同向、反向或汇聚的道路。如果这两条参考线相互不连接，则也无法实现道路连接。

In OpenDRIVE, road linkage is represented by the <link> element within the <road> element. The <predecessor> and <successor> elements are defined within the <link> element. For virtual and regular junctions, different attribute sets shall be used for the <predecessor> and <successor> elements.

在OpenDRIVE中，道路连接用 <road> 元素里的 <link> 元素来表示。 <predecessor> 以及 <successor> 元素在 <link> 元素中被定义。对于虚拟和常规的交叉口来说， <predecessor> 以及 <successor> 元素必须使用（shall）不同的属性组。

Attributes 属性

Follows the road header if the road is linked to a successor, a predecessor, or a neighbor. Isolated roads may omit this element.

如果道路与一条后继、前驱或相邻道路连接，该属性则遵循道路头文件。孤立的道路可（may）忽略该元素。

For virtual and regular junctions, different attribute sets shall be used. @contactPoint shall be used for regular junctions; @elementS and @elementDir shall be used for virtual junctions.

必须（shall）将不同属性用于虚拟以及常规的交叉口。@contactPoint须（shall）用于常规交叉口；@elementS 和 @elementDir则须（shall）用于虚拟交叉口。

Rules 规则

The following rules apply to road linkage:

以下规则适用于道路连接:

Related topics 相关内容

The road type defines the main purpose of a road and the associated traffic rules. Example road types are motorways and rural roads. The road type is valid for the entire road cross section.

道路类型（例如高速公路以及乡村公路）定义了道路的主要用途以及相关的交通规则。道路类型对于整个道路横截面均有效。

The road type may be changed as often as needed within a <road> element. This may be done by defining different road types at given points along the reference line. One road type remains valid until another road type is defined.

通过在沿参考线的给定点上定义不同道路类型，可（may）在 <road> 元素中根据需要改变道路类型。道路类型将持续有效，直到另一个道路类型被定义。

In OpenDRIVE, the road type is represented by the <type> element within the <road> element. The road type itself is given in the @type attribute.

在OpenDRIVE中，道路类型用<road>元素中的 <type> 元素来表示。道路类型本身在@type属性中被给定。

Attributes 属性

A road type element is valid for the entire cross section of a road. It is valid until a new road type element is provided or until the road ends.

道路类型元素对于整个道路横截面持续有效，直到新的道路类型元素出现或者道路结束。

Rules 规则

The following rules apply to road types:

以下规则适用于道路类型:

Related topics 相关内容

There are several ways to elevate a road or parts of a road:

以下几种方法用于标高道路或道路的部分:

The types of road elevation are shown in figure 39

道路高程的类型参见图39。

The s length does not change with the elevation.

s长度不随着高程变化。